The relationship between theory and practice is the key for Mao Zedong to realize the localization of Marxism. A correct understanding and handling of this problem is an important guarantee to win the victory of the Chinese revolution and construction under the leadership of the Chinese Communist Party. Different from many dogmatists clung to the doctrine and empiricists heavily relied on the experience, Mao Zedong insists on the concrete historical dialectical combination with the essence of Marxism and Chinese social practice, objects to the subjectivism knowing route, the right capitulationism theory and the “left” leaning reckless adventurism. Mao Zedong is good at summing up experience and abstracting out Marxism essence according to the experience of the practice, flexible and duly adjusted the theme, process and method of the practice, which makes Marxism acquire a realization form on Chinese land. This will be of very importantly methodological significance for the historical process of improving the localization of Marxism in China