Based on the concept of sustainable development， whether and how the positive performance of ESG responsibilities affecting the value of firms has been widely concerned and discussed. It empirically examined the impact of ESG performance on the book value and market value of firms by using A-share companies listed on the Shanghai and Shenzhen Stock Exchanges in China from 2009 to 2021 as the sample group. At the same time， based on the perspective of firms’ innovation investment decision-making， it discussed the mediating effects of firms’ innovation investment level and innovation investment structure in the above process. The results show that there is a significant difference in the impact of ESG performance on the book value and the market value of firms. Good ESG performance is conducive to increasing the book value of firms， but has a significant negative impact on the market value of firms. ESG performance has a positive impact on the book value and market value of firms by increasing the level of innovation investment， but has not had an impact on the book value and market value of firms through the channel of adjusting the structure of innovation investment. The conclusions not only enrich the research results of the impact of ESG performance on firm value and its mechanism， but also provide feasible practical implications for stimulating the internal motivation of firm to fulfill its ESG responsibility and enabling firm value improvement through innovation investment decisions.