Taking a-share listed companies in Shanghai and Shenzhen Stock Exchanges from 2012 to 2018 as samples, this paper conducted an empirical study on the relationship between financial constraints, investment efficiency and corporate performance. It is found that the degree of financial constraint is negatively correlated with the investment efficiency of enterprises, that is, the higher the degree of financial constraint is, the lower the investment efficiency of enterprises is. Investment efficiency is positively correlated with enterprise performance. For enterprises with different investment efficiency, the impact of financial constraint on enterprise performance is different. Compared with enterprises with high investment efficiency, the financial constraint degree of enterprises with low investment efficiency has a greater negative impact on enterprise performance. Based on the theory of financial investment balance, this paper suggests some approaches to deal with financial constraints and investment efficiency.