Internal control is one of the key problems of enterprise management, internal control quality directly influences the growth and development of the enterprise. In light of contract theory, this paper makes an analysis on problems existing in internal control of enterprises and finds that there do exist the following problems: the internal control system is imperfect, the design is unreasonable; internal control supervision mechanism is not sound and the enforcement is not strong. What's worse, the enterprise management do not have a clear understanding of internal control and their risk awareness is quite weak. Furthermore, market acceptance of internal control information is not strong and the external supervision mechanism is not perfect. On the basis of those mentioned above, the construction strategy of optimizing the internal control of enterprises is put forward from the angle of the enterprise and the government respectively.