On 1 July 1997, Hong Kong became a Special Administrative Region of the People's Republic of China, enjoying a high degree of autonomy under the principles of "one country, two systems" and "Hong Kong people administering Hong Kong".
The Basic Law is the constitutional document of the Hong Kong Special Administrative Region (HKSAR) and the blueprint for HKSAR's future development. Specific provisions have been laid down in the Basic Law on the changes brought about by this new status and on the implementation of the concept of "one country, two systems".
Under the Basic Law, the HKSAR shall enjoy a high degree of autonomy except in those matters relating to defence and foreign affairs. Also, the HKSAR shall exercise executive, legislative and independent judicial power, including that of final adjudication. The HKSAR's executive authorities and legislature shall be composed of permanent residents of Hong Kong.
The HKSAR shall remain a free port, a separate customs territory and an international financial centre and may, on its own, using the name of "Hong Kong, China", maintain and develop relations and conclude and implement agreements with foreign states and regions, and international organisations in the appropriate fields, including the economic, trade, financial and monetary, shipping, communications, tourism, cultural and sports field.
Further information about the Basic Law can be found here.