Abstract:    Under the downward pressure of domestic and foreign economy, "Tax reduction and Fee reduction" has become an important means to enhance the vitality of enterprises and promote high-quality development. Different from other tax policy reforms, the social insurance premium reduction policy will affect the development of enterprises through two aspects: financial capital and human capital. However, the impact and mechanism of the policy on the high-quality development of enterprises are not clear. Based on this, this paper takes the social insurance premium reduction policy implemented by various prefecture level municipal governments as an exogenous event, using difference-in-difference (DID) model, and examines the impact of the social insurance premium reduction policy on the high-quality development of enterprises from the micro perspective of enterprise technological innovation. The results show that the social insurance premium reduction policy is conducive to improve the level of enterprise technological innovation. Further analysis shows that the social insurance premium reduction policy mainly promotes enterprise technological innovation by increasing R&D investment and optimizing personnel structure, but there are differences in the impact of the two paths: it can promote enterprise substantive innovation and strategic innovation through R&D investment, and it can only promote enterprise substantive innovation through personnel structure. Finally, the heterogeneous analysis shows that the above effects are more significant in state-owned enterprises and enterprises with better regulatory environment. The research conclusions of this paper not only provide incremental evidence for the research in the field of "Labor economics and Micro enterprise behavior", but also provide theoretical support for "Tax reduction and Fee reduction" and other business environment optimization measures. Innovation is the strategic support for building a modern economic system, but the lack of innovative talents, excessive tax burden on R&D talents and high labor cost are all important factors to inhibit enterprise innovation. 
   The research conclusion has important policy enlightenment and practical significance. First, under the downward pressure of the economy, how to revitalize enterprises has become an important problem for high-quality economic development. Since 2015, the central government has repeatedly announced the policy of reducing social insurance rates. The goal of the social insurance premium reduction policy is to "release water to raise fish" and obtain the long-term and high-quality development of enterprises and economy at the expense of the government′s short-term interests. However, the implementation of the policy of tax reduction and fee reduction has brought huge financial pressure to the government. What is the significance of the implementation of the tax reduction and fee reduction policy and whether it needs to be continued has become a prominent problem faced by the current government′s finance work. This paper finds that the implementation of social insurance premium reduction policy can promote enterprise technological innovation. It provides confidence and theoretical evidence for the implementation of the social insurance premium reduction policy. Secondly, for enterprises, the dividend of the social insurance premium reduction policy is not only to reduce the burden, improve cash flow and anti-risk ability. The research of this paper shows that the social insurance premium reduction policy can improve the personnel structure and promote the level of technological innovation of enterprises. Therefore, enterprises should seize this policy dividend, further optimize the personnel structure, and realize the improvement of quality and efficiency through the upgrading of their own innovation level.

Key words: social insurance premium reduction policy, enterprise technology innovation, mechanism