Abstract: Under China's "dual-carbon" goals, examining the impact of the carbon emissions trading system on corporate value is of great significance for achieving synergies between environmental protection and corporate development. Using A-share listed companies in Shanghai and Shenzhen as the research sample, this study applies the event study method and a multi-period difference-in-differences model to investigate the short- and long-term effects of the carbon emissions trading system on corporate value. The empirical results show that the system reduces corporate value in the short term but enhances it in the long term. This positive long-term effect is mainly realized through promoting firms' technological innovation, and it is further strengthened by greater carbon market liquidity. Moreover, heterogeneity analysis indicates that the long-term value-enhancing effect is more significant for state-owned enterprises and firms located in regions with higher levels of financial development. These findings provide important theoretical implications for improving market mechanisms, strengthening innovation incentives, and implementing differentiated policy guidance to transform emission-reduction pressure into long-term corporate value growth.