Abstract:In the 90 years’ history of the Communist Party of China, two campaigns aiming to rectify the Leftist tendency were launched, leaving behind serious historic lessons. The essence of the 90 years’ development of CPC is but to use the Marxist view and methods to study and solve problems, to promote China’s national and social liberation and modernization. At present, the most important task of the CPC’s is to build China into a highly democratic, prosperous, harmonious and stable country that believes in the rule of law. CPC should have an open mind and a world view so as to summarize the useful past experiences. In building a modern country of rule of law, the scientific development in the process of modernization and the proper handling of the international challenges affect the overall schema of building the whole society into a welloff one. And the most urgent problem faced by CPC is how to build it into a mature modern democratic ruling party, how to insist on the thinking route of being realistic, how to promote the democracy within the Party, and how to follow the mass line.