Under the background of China's anti-corruption campaign in recent years, the research on public corruption perceptions has become a hot topic in the field of anti-corruption. Existing researches mainly explain and analyze the differences of public corruption perceptions of government from the perspectives of politics, economy and culture, government anti-corruption performance and source of media information channels, but ignore the influence of class differences within the public on their corruption perceptions and their internal mechanism. Based on the empirical analysis of 2016 survey data of the situation of the national anti-corruption,the resultsindicate that:holding the other constants, (1)there is a significant correlation between the public social class status and corruption perceptions, which shows the characteristics of the “U” type on the whole, (2) and public inthe middle class has a significantly lower level of corruption perceptions. In the ordinal Logit regression model of central, provincial, municipal and county/district governments, the probability that the middleclass would significantly decline their perceptionslevel of corruption to the corresponding level of government is 13.20%, 67.03%, 49.03% and 68.88%, respectively, compared with the public who rated themselves as lower-class. At the same time, compared with the lower-class, the lower middle-class and the upper-middle class are also more likely to think that governments at all levels have a lower level of corruption. Except for the model of county government, the perceptionsdifference between the upper class and the lower class is not significant. This result is still true even after controlling the mediating variables such as corruption tolerance and anti-corruption satisfaction. Therefore, the internal reason may be closely related to the conservative tendency of the middle class in political character. Subsequently, the results of robustness check of larger samples are basically consistent. Further analysis of mediating effect by Sobel test methoddemonstrates that the differences in corruption tolerance, anti-corruption satisfaction, corruption experience and perceptions information source of different social strata and etc., are the important internal influencing mechanism that causes the differences incorruption perceptions. In particular, the degree of anti-corruption satisfaction and corruption tolerance are relatively high in mediating effect of each model, while the mediating effect of corruption experience and perceptionsinformation source is relatively low and unstable. The above results indicate that although the anti-corruption efforts of the government have been acknowledged by middle class in recent years, the fact that the lower-class have highercorruption perceptions of governments at all levelsuggests that the government should optimize its anti-corruption strategies in the future and pay more attention to solving the corruption problems which are in close proximity to the people.