"One country, two systems" (1C2S) is a constitutional principle of the People's Republic of China (PRC) describing the governance of the special administrative regions of Hong Kong and Macau.
Deng Xiaoping developed the one country, two systems concept. This constitutional principle was formulated in the early 1980s during negotiations over Hong Kong between China and the United Kingdom. It provided that there would be only one China, but that each region would retain its own economic and administrative system. Under the principle, each of the two regions could continue to have its own governmental system, legal, economic and financial affairs, including trade relations with foreign countries, all of which are independent from those of the mainland. The PRC has also proposed to apply the principle toward unification with Taiwan; however, Taiwan has consistently rejected the proposal.
Background Deng Xiaoping developed the principle of one country, two systems in relation to Hong Kong, Macau, and Taiwan. Hong Kong and Macau had been colonised by European powers and Taiwan remained under Kuomintang control at the end of the Chinese Civil War. According to Radio Free Asia, the theoretical framework for the "one country, two systems" principle for Hong Kong was first developed by Wang Huning and Wang Bangzuo in an unpublished article in the early 1980s.
In the context of Hong Kong
Hong Kong was a colony of the United Kingdom, ruled by a governor appointed by the monarch of the United Kingdom, for 156 years from 1841 (except for four years of Japanese occupation during WWII) until 1997, when it was handed over to the Chinese government.
In discussing Hong Kong's future, Deng described the risk of possible instability which might be caused by what he termed as destructive forces both inside and outside Hong Kong. In Deng's view, these destructive forces might create instability both prior to and after Hong Kong's return to China. Deng repeatedly stressed that the central government would need to intervene in Hong Kong affairs from time-to-time. Among other occasions, Deng told Hong Kong delegates to Beijing in 1984 that certain interventions would be necessary, that when turmoil occurs in Hong Kong the central government should intervene, and that it would be necessary to see if interventions would be in the interests of Hong Kongers and Hong Kong's stability and prosperity. In 1988, Deng stated that Hong Kong's political system was neither the British nor American systems and Hong Kong should not import Western political systems in the future.
Prior to Hong Kong's return to China, China and the UK signed the Sino-British Joint Declaration, a treaty which stipulated the drafting and adoption of Hong Kong's organic law Basic Law before the handover. The Hong Kong Basic Law ensured that Hong Kong will be granted autonomy in regard to its capitalist economic system and own currency (the Hong Kong dollar), legal system, human rights, and legislative system as a special administrative region (SAR) of China for 50 years. The current arrangement has permitted Hong Kong to function as its own entity under the name "Hong Kong, China" in many international settings (e.g. the WTO and the Olympics).
During the drafting of the Basic Law, Deng stated that universal suffrage and Western political systems were not appropriate for Hong Kong. Deng also stated that if Hong Kong became a base for anti-mainland China sentiment under the guise of democracy then China's central government should intervene.
The Chinese renminbi is not legal tender in Hong Kong. Likewise, the Hong Kong dollar is not accepted in stores in mainland China. With this arrangement, a permit or special visa () is required when passing between the borders of Hong Kong and mainland China, and people in Hong Kong hold Hong Kong SAR passports rather than Chinese passports. The official languages are a major factor besides the history of the former colony that has made Hong Kong and mainland China distinct from each other, as Cantonese and English are the most widely used languages in Hong Kong, while Mandarin is the official language of mainland China. The central government in Beijing maintains control over Hong Kong's foreign affairs as well as the legal interpretation of the Basic Law. The latter has led democracy advocates and some Hong Kong residents to argue that the territory has yet to achieve universal suffrage as promised by the Basic Law, leading to mass demonstrations in 2014.
In the context of Macau
A colony of Portugal for 442 years from 1557, Macau was returned to the Chinese government in 1999. In the Joint Declaration on the Question of Macau, the drafting and adoption of Macau's organic law before its return was foreseen. Like Hong Kong, a basic law would ensure that Macau retained its economic system, currency (the Macanese pataca), legal system (which is based on Portuguese civil law), legislative system, and human rights for 50 years, as a special administrative region (SAR) of China. The agreement has permitted Macau to function as its own entity in many international settings (e.g. WTO) rather than as a part of China.
As Macau has its own currency, the Chinese renminbi is not legal tender in Macau; the pataca is also not accepted in stores in China.
In the context of Taiwan
In addition to the Hong Kong and Macau contexts, Deng proposed the principle's applicability to Chinese unification, but the government of Taiwan has consistently rejected the proposal . According to polls conducted by Taiwan's Mainland Affairs Council in 2025, over 80 percent of Taiwan reject "one country, two systems".
Application to Hong Kong and Macau
Chinese paramount leader Deng Xiaoping proposed the principle during negotiation with British prime minister Margaret Thatcher over the expiration of the United Kingdom's lease on the New Territories (including New Kowloon) of Hong Kong in 1997. The same principle was proposed in talks with Portugal about Macau.
The principle is that, upon reunification, despite the practice of socialism in mainland China, both Hong Kong and Macau, which were colonies of the United Kingdom and Portugal respectively, could retain their established system under a high degree of autonomy.
Chapter 1, Article 5 of the Hong Kong Basic Law, the constitutional document of the Hong Kong Special Administrative Region, reads:
The establishment of these regions, called "special administrative regions" (SARs), is authorised by Article 31 of the Constitution of China, which states that the state may establish SARs when necessary, and that the systems to be instituted in them shall be prescribed by law enacted by the National People's Congress in light of the specific conditions.
The SARs of Hong Kong and Macau were formally established on 1 July 1997 and 20 December 1999 respectively, immediately after the People's Republic of China (PRC) assumed sovereignty over these respective regions.
Framework The two SARs of Hong Kong and Macau are responsible for their domestic affairs including, but not limited to, the judiciary and courts of final appeal, immigration and customs, public finance, currencies and extradition. The SARs are also exempt from mainland laws mandating the use of simplified characters in publishing and Mandarin in public education and most broadcasting. The diplomatic relations and military defence of the two SARs however, is the responsibility of the Central People's Government in Beijing.
Hong Kong continues using English common law while Macau continues using the Portuguese civil law system.
Names When the two regions have their own membership in international organisations (such as the WTO and the Paralympics), both regions are mandated to use the name "Hong Kong, China" or "Macao, China" instead of "Hong Kong" or "Macau"/"Macao", as stipulated several times under Chapter VII ("External Affairs") of both regions' Basic Laws.
For example, in Trade Policy Review documents between Hong Kong and the WTO, the documents use "Hong Kong, China" throughout even in prose. When a short name is used, it uses the acronym "HKC" and never "Hong Kong" or "HK" standalone. Similarly, in Trade Policy Review documents between Macau and the WTO, "Macao, China" is used in prose throughout and the only short name used is the acronym "MSAR".
Potential extension Several high level members of the government have expressed a potential extension of the system beyond 2047 for Hong Kong. In January 2020, Carrie Lam stated that "My view is this: as long as we persist with the "One Country, Two Systems" principle, push forward the implementation of 'One Country, Two Systems' and have a full understanding and implementation of the principle... then we have adequate reason to believe that 'One Country, Two Systems' will be implemented smoothly and in the long term, and it will not change after 2047."
Additionally, in a June 2020 online webinar to campaign for the National Security Law, Zhang Xiaoming said that the National Security Law would ensure that the freedoms granted to the city can be extended beyond 2047. However, neither Carrie Lam or Zhang Xiaoming have promised such an extension or laid out concrete steps or goals in order for it to happen.
In October 2021, Carrie Lam reiterated that she believed the system would be extended beyond 2047, stating "Anybody would seriously ask: why do we have to change it? But of course, something more concrete will have to come out later on to give the needed assurance about the continuation of the common law system, the monetary system, the professional recognition system, maybe some land leases."
In March 2022, Xia Baolong, head of the Hong Kong and Macau Affairs Office, said that after 2047, the "one country, two systems" could be extended by another 50 years, until 2097. In July 2022, Leung Chun-ying, former chief executive, said that he expected the system to be extended past 2047. On 1 July 2022, during a visit to Hong Kong, General Secretary of the Chinese Communist Party Xi Jinping made a promise that the system is a long-term policy. In February 2024, Xia Baolong said that the system would be kept permanently.
Implementation in Hong Kong Degree of autonomy As a British colony, Hong Kong was neither democratic nor autonomous. After Britain returned Hong Kong to China in 1997, Beijing promised that Hong Kong citizens would be free to elect their local government. However, the Basic Law does not have a clear timetable for when universal suffrage is to be achieved, ultimately stating that a full vote by the populace and universal suffrage must be reached before the end of the 50-year transition according to Article 45.
In the year after the handover, surveys showed high levels of satisfaction with Beijing's hands-off relationship with the former colony.
The year before, the Provisional Legislative Council passed laws restricting the right of abode, leading to a case brought against the government, which ended in a loss for the government in the Hong Kong Court of Final Appeal in 1999. The government then took its case to the National People's Congress. The legal establishment expressed its disapproval of the act Martin Lee described as "giving away" Hong Kong's autonomy with a silent march. Polls showed the events had depressed the public's confidence in the government, despite the fact that most were in favour of the government's stance over that of the court's.