Abstract: Purpose/Significance High investment efficiency ensures that enterprises can effectively apply funds to correct investment projects to support the strategic development of enterprises. The purpose of strategic change is to enhance the competitiveness of enterprises, thereby improving the performance of enterprises. Exploring the relationship between investment efficiency and strategic change is important to improve the success rate of corporate strategic reforms, create and maintain their own competitive advantages. Design/Methodology This paper takes listed companies in Shanghai and Shenzhen from 2014 to 2018 as a sample, through a two-way fixed effects regression model, and studies the relationship between investment efficiency and strategic change and the adjustment effect of TMT optimism on the relationship between the two, and further dissects the influence of the intensity of competition on the optimistic regulation of TMT. Conclusions/Findings (1) Investment efficiency positively influences strategic changes. (2) TMT optimistically negatively regulates the positive relationship between investment efficiency and strategic change. (3) With the increase of competition intensity, the negative moderating effect of TMT optimism on the positive relationship between investment efficiency and strategic change is weakened. (4) This paper expands the literature on investment efficiency, strategic change, and managerial optimism.