Abstract:    New energy enterprises is the deep integration of new industry and new technology, which need to promote firm performance by continuing R&D investment to maintain core competitiveness under the background of fast technology update speed. R&D innovation is an important means to break the technological bottleneck and improve the competitiveness, but the public nature of R&D activities makes enterprises bear all the R&D costs, but not all the R&D benefits. Given the volatility of innovation activities and the need for sustained and stable long-term investment to break technological bottlenecks, government intervention and necessary support are needed to correct market failures in the innovation process. Government subsidies, as the main source of enterprise R&D funds, are the most common incentive measures, especially in the capital-intensive and technology-intensive new energy industries. Government subsidy is the key factor that drives enterprises to carry out R&D activities.At present, China government subsidizes the new energy enterprises heavily, but there is a gap between the intensity of our enterprises′ R&D investment and the international standards. Therefore, based on the panel data of new energy listed enterprises from 2012 to 2016, a fixed-effect model is used to explore the relationship between government subsidy, R&D investment and firm performance, and reveal the intermediary mechanism of R&D investment. Furthermore, group regression analysis was conducted to analyze the difference of the effect of government subsidies on firm performance under different enterprise nature and regional characteristics. The results show that government subsidy has a positive effect on R&D investment, especially in the eastern coastal area (vs. non-eastern coastal area) and non-state-owned enterprises (vs. state-owned enterprises). Current and delayed R&D investment has a positive effect on firm performance, especially in non-state-owned enterprises (vs. state-owned enterprises) .The government subsidy in the current period and the 1st lag period has the promotion effect to the enterprise performance, and passes through the intermediary function of the R&D investment completely.With the rapid development of new energy enterprises, government subsidies can provide additional R&D funds for enterprises, but the utilization rate and effect of subsidies are different in different market environments and enterprise systems. How to screen and select high-quality enterprises to give policy support so that achieve the optimal allocation of resources has become the core issue that policy makers focus on.Based on the above conclusions, this article put forward relevant policy recommendations for the government and firm respectively.For the government, first of all, government should refine the supporting policies for subsidies, stand by them from various aspects such as taxation, laws and research personnel, increase the subsidy policies for the eastern coastal areas and non-state-owned enterprises, and formulate supporting policies to stimulate state-owned enterprises to increase their R&D enthusiasm so as to improve the efficiency of R&D subsidy in state-owned enterprises. Secondly, government should optimize the external business environment of new energy enterprises, perfect the financing channels of enterprises, realize the best allocation of market resources, strengthen the supervision of subsidy after it enters the enterprises, increase the transparency of subsidy, and reduce the rent-seeking behavior of enterprises. Finally, government should strengthen the policy guidance and innovation incentive, construct the performance evaluation system to enhance the enterprise′s independent innovation consciousness, and stimulate its R&D investment to keep the new energy market healthy development.For the enterprises, as the main body of innovation, new energy enterprises should make full use of government subsidies to maintain the stable development and performance improvement of enterprises. First of all, enterprises should strive for government subsidies and increase R&D investment, especially the midwestern enterprises and non-state-owned firms, make full use of existing resources to increase R&D investment intensity, and promote enterprises′ own performance. Secondly, enterprises should pay attention to the efficiency of R&D output while increase R&D input, especially the state-owned new energy enterprises. The state-owned firms should optimize the budget cost management and personnel administration management in the R&D process to maximize the efficiency of R&D subsidy utilization. Finally, new energy enterprises should strive for government subsidy to alleviate their R&D pressure and achieve innovation output with the help of existing R&D resources, so as to improve their performance effectively.The innovation points are as follows: Firstly, on the basis of considering the time lag effect, the paper empirically analyzes the path of government subsidy to enterprise performance, and expands the related literature of government subsidy and enterprise R&D behavior in the field of new energy. Secondly, it further reveals the effect boundary of firm and regional heterogeneity on its mechanism, which provides a new theoretical basis for this problem. Thirdly, it′s different from previous studies which focused on innovation performance and financial performance, this paper selects the rate of growth of operating income to measure the performance of enterprises, so as to better reflect the growth ability and development ability of new energy enterprises. The conclusion of this study is more pertinent to the actual situation of the new energy enterprises in which the technology is updated quickly.

Key words: new energy, government subsidy, R&D investment, firm performance, heterogeneity