Abstract: In western academic community,there are three kinds of views on the relationship between democracy and corruption.The first points out that democracy and corruption are not connected.The second points out they are closely connected and the relation is linear which means democracy is conducive or not conducive to corruption.The third theory points out that the relation between them is nonlinear which means the level of corruption is different at different stages of democratization and includes three models:" inverted-U type","S-type" and "J-type".Researches on the relationship between democracy and corruption have achieved progress,making the transformation from static and qualitative study to dynamic and quantitative study.