Abstract: The marketization of China's economy is constantly improving. However, the principal-agent problem of state-owned enterprises is serious under the previous assessment and incentive mechanism. In 2013, the Third Plenary Session of the 18th Central Committee of the Communist Party of China reaffirmed the importance of promoting mixed ownership reform, hoping to solve the problems of "absence of owner" and "principal-agent" by taking advantage of the reform of the governance structure. In addition, in order to cope with the challenges posed by the downturn in the international economic cycle and increased competition in the international market, China urgently needs to cultivate "going out" state-owned enterprises with international competitiveness, actively respond to the mixed ownership reform policy and make use of the comparative advantages of the professional capability of institutional investors and the international experience of foreign shareholders, so as to encourage them to foster new drivers of sustainable development in a more open environment. However, few studies have focused on the influence mechanism of mixed ownership reform on innovation performance of OFDI state-owned enterprises from the perspective of "reverse technology spillover". Therefore, this study divides the process of reverse technology spillover into two stages. The first stage is to promote OFDI of state-owned enterprises in the domestic environment (Out Stage), and the second stage is the reverse technology spillover stage of state-owned enterprises in the foreign environment (In Stage). Taking the state-owned listed manufacturing firms from Shanghai and Shenzhen stock exchanges as samples, based on a two-stage theoretical model from the perspective of reverse technology spillover, this paper studies the impact of the mixed ownership reform on innovation performance of OFDI state-owned enterprises mainly by empirical tests of instrumental variable method and moderated mediation effects. The results show that shareholder diversity introduced by non-state-owned shareholders has a significant positive impact on innovation performance of State-owned enterprises. And diversity of appointed directors introduced by institutional investors and foreign capital plays a partial mediating role between shareholder diversity and innovation performance. This mediating effect is positively moderated by the choice of overseas M&A and enterprises’ absorptive capacity. The results of this study not only enrich and expand the influence path and mechanism of mixed ownership reform on reverse technology spillover of state-owned enterprises theoretically, but also provide relevant enlightenment in management practice for the reform of governance structure and improvement of innovation level of state-owned enterprises. Based on the research conclusions, we put forward three enlightening countermeasures that include: firstly, it is important to strengthen the complementary advantages and supervision and restriction of state-owned and non-state-owned equity. State-owned enterprises need to introduce institutional investors, foreign capital and other non-state-owned shareholders to reform, promote the depth of integration and effective supervision and restriction in their governance structure, and give play to the comparative advantages of institutional investors and foreign shareholders in terms of innovation motivation and international experience. Secondly, state-owned enterprises should deepen the synergistic effect of diversity of appointed directors introduced by institutional investors and foreign capital. On the basis of promoting the reform of equity diversity with the participation of institutional investors and foreign capital, state-owned enterprises need to optimize the high-level governance structure and improve the quality of investment decisions through the heterogeneous and complementary board members appointed by institutional investors and foreign shareholders. At last, state-owned enterprises should take advantage of the positive effects of entry mode optimization and absorption capacity development. State-owned enterprises can focus on the diversification and flexibility of the choice of entry mode, so as to play a positive role in flexible transfer of property rights and technology spillover of partners in overseas M&A mode. In addition, while upgrading the development power of extroverted innovation, state-owned enterprises can strengthen the recruitment and training of R&D personnel worldwide, promote the development and utilization of international high-level human capital and intellectual capital, and constantly strengthen the positive effect of governance structure optimization and absorption capacity improvement on reverse technology spillover.