Through literature and Delphi method, the influencing factors of private enterprise investment efficiency are sorted out, and the DEMATEL-ISM-MICMAC model is creatively constructed, and the influencing factors of private enterprise investment efficiency are studied theoretically and empirically. It is found that financing constraints are the most critical factors affecting private enterprises in the construction of the DEMEL model, but the replacement of local officials is the deepest factor in the ISM model, and the turnover of local officials indirectly affects the investment efficiency of private enterprises by influencing financing constraints. This paper integrates the influencing factors of the investment efficiency of private enterprises for the first time to study together, presents the relationship between factors in the model, and provides a new method to improve the investment efficiency of private enterprises, which has important enlightenment and practical significance for the continuous low investment efficiency of private enterprises in China and the improvement of the private economy.