The investment activities of enterprises are an important link that affects the economic development of a country. How to promote the investment of social capital and mobilize the enthusiasm of private enterprises has always been a difficult problem for developing countries. The research on the influencing factors of enterprise investment decisions has a long history and is constantly deepening. In this chapter starts with a summary based on the institutional theory, resource dependence theory and behavioral theory of the firm. Second, the chapter reviews the literature on how public-private partnership policy affect firm operation, including public-private partnership policy analysis, and the impact of public-private partnership policy on private firm operation. Third, the chapter summarizes the research on the effect of policy uncertainty on firm operation.