Understanding the role in which the national audit plays in the state governance is a prerequisite for the efficient promotion of modernization of state audit service and state governance capacity.This article first analyzes the essence of national governance capacity used the theory of separation of powers，and then it proposes a theoretical framework to studies the role of national audit in the construction of national governance capacity.The paper insists that national audit plays an important role in ensuring the modernization of national governance capacity，especially；national audit is the monitoring mechanism of the modernization of national governance resources management.It is an important supervision mechanism of government and also an important guarantee of national governance risk prevention and the stability of the national governance order.