Abstract: This paper takes the coal listed companie s in 2013-2017 as the research sample, and empirically tests the relationship between overconfidence and innovation performance of China's coal enterprises, as well as the regulatory role of corporate debt when the size of enterprises is different. The results show that: the overall coal enterprise executives overconfidence suppresses innovation performance; when the corporate debt is high, the large-scale model coal enterprise executives overconfidence suppresses innovation performance, and the corporate debt plays a regulatory role; the small-scale model coal enterprise debt and innovation performance have an inverted U-shaped relationship. And put forward corresponding countermeasures and suggestions to promote the innovation and development of coal enterprises in China.