Audit system of one country generally includes national audit (government audit), CPA audit (civil audit) and internal audit. The worldwide development history of audit and experience of China’s current audit system indicates that audit is the result of fiduciary duty, but national audit, CPA audit and internal audit have different characteristics and advantages, and they play an important role in nation governance and corporate governance. The coordination and cooperation among these three audit bodies reflect the inter action of national governance system and corporate governance system, which could facilitate the national governance, and meanwhile improve the level of corporate governance.