This study uses the sample of the listed companies in Taiwan during 2011-2020. The purpose of this research aims to investigate whether excess cash holdings and financial constraints affect investment efficiency. The empirical results indicate that financial constraints could restrain overinvestment, and excess cash holdings doesn’t affect the investment efficiency. The more a firm is constrained, the less it will excess its investment. That is when a firm excesses its investment, financing constraints can decrease the blindly invest by its executives, and reduce the problem of excessive investment.