Based on the reality of China’s market economy reform and the theory of game theory and information economics, this paper first constructs a principal-agent model to analyze the impacts of remuneration, punishment and national audit on the abuses of government officials. Then, the paper analyzes how officials’ rent-seeking income and expected return of after-resign on the optimal strength of national audit in China by using the cost-benefit method. The main conclusions as follows: Firstly, external factors such as remuneration, punishment, audit and supervision, rent-seeking income and expected earnings after-service all affect government officials’ abuse of public power. Secondly, the optimal audit strengthen of the government depends on the cost of government supervision, the grade of the officials, and the other factors. The higher grade of officials the higher level of auditing. Thirdly, with the deepening of marketization of China’s economy and the increasing resources held by the government, the incomes of rent-seeking government officials and the expected remuneration after leaving the government become higher and higher, and the auditing and supervision on government officials should also be strengthened. The study provides a theoretical basis for China’s national audit strategy.