The understanding of the truth proposition of "Only socialism can save China,and only socialism with Chinese characteristics can develop China" has been acquired by the Chinese people and Chinese Communists in the process of repeated comparisons and hard explorations.For the Communist Party of China,from its establishment in 1921 up to 2011,its understanding of socialism has experienced in general four main periods:before and after the Party’s founding,new democratic revolution,transition to socialism and all-round socialist construction.