Adopting the subjective indicator of corruption tolerance, this paper measures the change of moral attitudes towards corruption among civil servants since the18th National Congress of the Communist Party of China (CPC) to test the effectiveness of the construction of the anti-corruption system on individuals’ moral development. The questionnaire on corruption tolerance conducted among civil servants from 2012 to 2017 reveals that the corruption tolerance after the 18th CPC National Congress is lower than that of before. Moreover, the corruption tolerance has seen a downward trend since 2012, and threenodes can be observed: firstly, the tolerance corruption in 2013 was significantly lower than that in 2012; secondly, corruption tolerance slightly increased in 2014 and 2015 compared with 2013; finally, corruption tolerance showed a downtrend from 2015 to 2017.By exploring the influence of institutional factors on corruption tolerance, this paper finds that the driving factor for the decline of corruption tolerance is that the anti-corruption strategies have been changing from the centralized and power-styled modeto institutionalization and normalization, as well as a combination of the construction of static institutions and a dynamic mechanism for sustainableimplementation. These measures have led to the improvement of both institutional constructionand individual morality. The shift from passive obedience to activerecognition of the moral normsconforms to Kohlberg’s theory of moral development. Correspondingly,civil servants’ attitudes toward corruption went through three phases: The first is the stage of imposed obedience under intensified anti-corruption actions, during which the decline in the corruption tolerance was more out of fear of high-handed punishment than out of identification with anti-corruption. At this stage, the civil servants’ obedience mainly developed from external compulsion. They obeyed authorities and superiors in order to escape punishment, and their capability of moral responsibility was still at the stage of compulsorily passive obedience. The second phase is the moral deviation in the initial stage of system construction, during which the anti-corruption started to transform from being power-driven to system construction. As a result of the prevailing culture of corruption in the past, after a brief shock, civil servants began to slack off and held negative attitudes towardanti-corruption, and along with their increasing expectation of corruptive opportunities after the power transition, thetolerance of corruption increased. The third phase is “conventional morality” in the period of institutional strengthening, during which civil servants’ corruption tolerance declined again. The attitude of civil servants toward corruption began to show certain characteristics of the conventional moral phase, that is, civil servants began to develop a more rational understanding of authority and orders. Their attitudes toward anti-corruption institutions changed from passive obedience to positive identification. This paper shows that the construction of an effective anti-corruption system requires not only static laws and regulations, but also a sustainable long-term enforcement mechanism. The individual morality of civil servants can be developed and perfected in the continuous and stable institutional construction and implementation.