Mao Zedorg's The theory of Practice focuses on the relation between knowledge theory and practice, which gives a systematic and profound interpretation on the interrelation of knowledge and practice, the developing process of knowledge, absolute truth and relative truth in Marxist epistemology, and some major philosophical problems such as remolding the relation between the objective world and the subjective world. Mao’s viewpoint of practice enriches Marxist epistemology and the Mass Line of the Party, prompting the combination of Marxism and its practice in china. Since the 18th Party Congress, theoretical innovation based on practice has been pushed further forward, and the construction of socialism with Chinese characteristics has been ligoroudy promoted. Studying, developing and fulfilling Mao Zedong's viewpointg of practice bear great epochal value and profound historic significance.