The participation of private capital in the mixed ownership reform of SOEs is an important measure to maintain and increase the value of state-owned assets. From the theoretical perspective of sharing economy, this paper uses Chinese data to study the impact of private enterprise participation on the high quality of state-owned mixed enterprises. This paper draws the following conclusions: (1) The participation of private enterprises can significantly improve the development quality of state-owned mixed enterprises, and this conclusion is also valid after dealing with the endogenous problem of the model. (2) The empirical results of profit-sharing heterogeneity show that when SOEs are willing to share their profits with private enterprises, private enterprises may show high vitality, which has a more obvious effect on improving the development quality of state-owned mixed enterprises. Therefore, in the process of reform, SOEs should be encouraged to transfer part of their profits to private enterprises, and at the same time, efforts should be made to create a good environment for the development of private enterprises, so that private entrepreneurs can fully stimulate their own entrepreneurial spirit.