Recently, there have been many negative events in the Government Accountability Office (GAO) and the Office of the Inspector General(OIG), which is a reflection of the situation of political division in the audit field.The reason for the formation of the US Federal audit system lies in the lack of checks and balances brought about by the expansion of the executive power in the mechanism of separation of powers and checks and balances. Its institutional authority mainly stems from the internal needs of the political system, the objective and neutral position of the third party, the professional level and the corresponding institutional guarantee. With the separation of powers and checks and balances system being coerced by partisanship, the audit system has been frequently politicized and used as a tool, which has deeply shaken the authority and credibility foundation, and will not ease easily with the change of moderates.