MACAO, Feb. 21 (Xinhua) -- China's top legislator Wu Bangguo said implementing the "one country, two systems" policy is "epoch-making" during his keynote speech at a conference marking the 20th anniversary of the promulgation of the Basic Law of Macao on Thursday.

　　Wu said the concept within the People's Republic of China where the mainland maintains a socialist system, while Hong Kong and Macao retain capitalist systems, is a great one and unprecedented.

　　Wu, chairman of the National People's Congress (NPC) Standing Committee, arrived in Macao Wednesday for a three-day visit to celebrate the 20th anniversary of the promulgation of the Macao Special Administrative Region (SAR)'s Basic Law.

　　He stressed a thorough understanding of the relationship between the mainland pursuing socialism and Macao capitalism as crucial in promoting Macao's Basic Law.

　　Only when the concept is completely understood can the "one country" principle be upheld and the differences between two systems be respected, and both remain unchanged, Wu said.

　　He said such a policy could work primarily because the Chinese mainland and Macao share the same goal -- prosperity for the country and a better life for the Chinese people.

　　He stressed that Macao practicing capitalism comes under the premise that the Chinese mainland pursues socialism.

　　The Basic Law of the Macao SAR was promulgated on March 31, 1993 and took effect on Dec. 20, 1999, when the government of the People's Republic of China resumed exercising sovereignty over Macao. It has acted as the cornerstone of the region's political and legal systems.