Abstract:    China′s new energy vehicles is a strategic emerging industry, which is urgent for the government to implement relevant industrial policies to support them. Since 2009, the Chinese government has successively introduced "supportive" policies by means of subsidies and incentives and "threshold" policies by means of standard constraints in order to accelerate the development of the new energy vehicle industry. Although the development of the new energy vehicle industry cannot be separated from the support of various "supportive" policies, unreasonable "supportive" policies also lead to enterprises to carry out "strategic" innovation, fabricate false sales data and other "fraud" problems. Under this situation, it is particularly important to evaluate the "supportive" and "threshold" policy innovation incentive effects of new energy vehicles, and study which type of policy tools can better adapt to the current development of China′s new energy vehicle industry and help China to move from a big automobile country to an automobile power.Theoretical studies on the innovation incentive effect of new energy vehicle industry policy mainly focus on two types: "supportive" and "threshold". For example, Dosi et al. (2006) and Chi et al. (2022) found that the "supportive" policy effectively stimulated the technological innovation of enterprises; A single "supportive" policy may disturb the market order (Dosi,1988); Different combinations of "supportive" policy tools have different impacts on innovation(Wang and Zhang ,2020), and both tax incentives and financial subsidies can promote the technological innovation of new energy vehicle enterprises. ZEV credits policies such as "double credits" have also significantly promoted the R&D investment of new energy vehicle enterprises (Melton et al.,2016; Li and Xiong,2021); Based on product attribute catalog standards, enterprises may "seek subsidies" for production instead of innovation (Chen et al.,2021). Compared with the previous studies, this paper provides a new perspective to test the similarities and differences between the two types of new energy vehicle industrial policies in terms of stimulating technological innovation. Based on the difference-in-difference model and a unified empirical analysis framework, this paper  selects listed companies in the new energy vehicle industry from 2007 to 2018 as research samples  and compares the innovation incentive effect and mechanism of the single policy and the synergy of the two policies. We find that: (1) Both types of policies have stimulated technological innovation of enterprises; the "threshold" policy has a greater innovation incentive effect than the "supportive" policy, and there are complementary effects between the two types of policies; the synergy of the two types of policies has a greater incentive effect on enterprise technological innovation than a single policy type. Our conclusions remain reliable after a series of robustness tests. (2) The mechanism test found that the "supportive" policies stimulated enterprise innovation by increasing R&D intensity and other resource compensation effects; while the innovation incentive effect of "threshold" policies was closely related to the degree of market competition: moderate market competition increases the incentive effect of the "threshold" policy on enterprise innovation, while excessive market competition inhibits the effect. (3) There is heterogeneity found at firm and regional level. Based on the above conclusions, this paper draws the following policy implications. First, the government should pay attention to the complementary coordination of "supportive" and "threshold" policies when formulating industrial policies. Second, promote industrial policies for new energy vehicles in an orderly way. In the implementation of "supportive" policy, we should give full play to the positive role of resource compensation in promoting enterprise innovation. When implementing "threshold" policies, we should adhere to market leadership and government guidance. Third, the government should accurately implement new energy vehicle industrial policies and continue to promote high-quality development of the new energy vehicle industry.

Key words: industrial policy, new energy vehicle, technological innovation, policy coordination