Nowadays, there is large amount of corruption in public investment and expenditure, huge and multiple fiscal supervision system didn't play an effective function. One important reason is that we lack an effective coordinated relationships among those supervisors. The two most important subjects in fiscal supervision system are People's Congress fiscal supervision and the government audit, which were carefully analyzed in this article as well as the method of their integration. Firstly, the essay analyzed the characteristics of NPC fiscal supervision and government audit supervision, advanced a concept of their integration, and further analyzed the foundation and constraints of their synergistic integration. On this foundation, the essay proposed the Target and integration of their synergistic integration. The essay considered that coordination on the government budget is the path of integration. Considered the current condition of financial supervision in China, the essay suggested that in order to enhance financial supervision efforts to curb investment and public expenditure in the field of public corruption, further cooperation between the NPC financial supervision authority and major projects and areas of priority sectors should be carried out in areas such as the audit budget management in the whole aspects, the entire process of tracking budget implementation monitoring and the supervision of major projects and key departments. Finally, the essay discussed the system construction from three aspects which are the construction of information platform, the improvement of law and regulations, the establishment of political participation mechanism and the establishment of a responsibility system.