Abstract: Democratic centralism is the most basic principle of China's politics.The concept of democratic centralism is compound and has multiple levels.In this paper,we will understand democratic centralism from three aspects.Firstly,as a organizational principle for political party,its core is centralism and the democracy is the method for centralism;Secondly,as a organization form for regime, it is a unified policy of democracy and centralism,and is integrated in the system of people's congresses design;Lastly,as a formulation principle for public policy,its core is democracy,and the democracy is throughout the whole process of public policy.In short,clearly defining the different dimensions of democratic centralism and its application in theory can help us correctly grasp the principle of democratic centralism in the political practice.Only in this way can we make it play a better role in all fields,and the misalignment and offside bringing about by the functional disorder won't be produced.