This study empirically tests the effects of the mixed-ownership reform of SOEs on the total factor productivity (TFP), the mechanisms, and the heterogeneity effect of different degrees of mixedownership reform on TFP. Based on the data of Chinese A-share listed state-owned enterprises (SOEs) from 2010 to 2020, this study draws several key conclusions. Firstly, the mixed-ownership reform of Chinese SOEs can improve their TFP. Secondly, in the dimension of governance, the mixed-ownership reform of Chinese SOEs can also improve their TFP, but the effect of improvement is smaller than that within the dimension of equity structure. Finally, corporate research and development (R&D) has a mediating effect on the relationship between the mixedownership reform of Chinese SOEs and their TFP. The results of this study are not only useful to provide countermeasures and suggestions for the mixed-ownership reform of Chinese SOEs, but also can be adapted to many other developing countries, especially for those in the transition and realize high-quality development through speeding up corporate R&D.