Because different countries have different concepts of political party at different stages of development of political parties,so the theory and practice of democracy is different.On the viewpoints of historical development,the Western political parties have a developing process from the elite party to the modern mass-party,and to the contemporary catch-all party and cartel party.Different party types have different characteristics,inner-relationships and inner-democratic.According to the degree of centralization within the party,the contemporary mainstream political parties can be divided into four types:oligarchy-authoritarian,centralization,limited centralization and decentralized political parties.Comparatively,the British Conservative Party tends to the type of oligarchy-authoritarian,the Labour Party tends to the type of limited centralization,the two major U.S.political parties belong to decentralized political parties,the two major political parties in Germany tend to the type of limited centralization,"United Russia Party" tends to the type of oligarchy-authoritarian,the Russian Communist Party belongs to the type of centralization.To comparatively analysis the types of parties and inner-party democracy can contribute to understand the essence,values,goals and limits of inner-party democracy,which can help us better understand the worldly diversity of the theory and practice of inner-party democracy.