Hong Kong was a British Crown Colony from 1841/2 until 1997. Its legal system was influenced by the English/common law tradition.
China resumed sovereignty of Hong Kong in 1997 with the undertaking that there would be "One Country, Two Systems" until 2047.
Hong Kong Special Administrative Zone therefore remains within the common law tradition, with English as one of its official languages.
The Basic Law came into force on July 1 1997.
The legislature is the Legislative Council. (Its legislation has to conform to the Basic law, and it cannot legislate in either defense or foreign affairs matters.)
The executive is headed by the Chief Executive who is supported by an Executive Council. The Government Secretariat and departments
The judiciary is independent.
The court of last resort is the Court of Final Appeal. The High Court hears both appeals and some first instance cases. Lower courts include District Courts and Magistrate's Courts.
There are also a number of tribunals with special jurisdictions: eg Lands Tribunal and the Labour Tribunal.