Based on the 2014-2018 financial report data of Chinese A-share listed private enterprises, this paper discusses the impact of economic policy uncertainty and accounting conservatism on the company"s investment efficiency. The empirical results show that the uncertainty of economic policy aggravates the inefficient investment of the company; the accounting conservatism plays a governance role in the investment activities of the company, which can effectively alleviate the over investment of the enterprise and improve the investment efficiency, but the accounting conservatism has no obvious effect on alleviating the insufficient investment of the company; the accounting conservatism is a cautious response to the uncertainty of economic policy, which can be restrained the negative effects of uncertain economic policies on the investment efficiency of companies.