Democracy is to strengthen the innovative vitality of political parties to consolidate the unity of the important guarantee. Democracy is not sufficient, is not active will seriously affect the role and function of political parties in the normal play. In today's communist movement at a low ebb of the situation, the proletarian party democracy is directly related to the party's ruling status, this paper, the Chinese Communist Party and the Communist Party of Cuba two typical example, through two different kinds of democratic construction of comparative to show its presence in the times of the democratic process of building the party in a different way to constantly improve the party's leadership, strengthen the whole party, people's cohesion, and ultimately the realization of democracy promote Party construct target.