Abstract:      With the development of global economic integration and the gradual relaxation of financial supervision, the cross-listing of A+H shares has become an important strategic choice for Chinese companies. Compared with pure A-share listed companies, A+H-share cross-listed companies face a more effective capital market environment, including more effective investor protection, stricter information disclosure environment, wider investor attention, better quality finance Intermediaries and more financing channels, which not only have an external governance effect on the companies, but also provide a better financing environment. Given the fact that corporate innovation is a long-term investment activity with high risk and high investment characteristics, the existence of agency problems and financing constraints make corporate innovation activities often over or under invested. Then, when companies from Chinese mainland go to Hong Kong, China to list, how will the mature capital market environment affect the company′s innovation?
    In order to answer the above question, we select the A+H share cross-listed companies from 2003 to 2017 as the research sample, and use multiple regression analysis, PSM, Heckman test and other methods to test the relationship between cross-listing and corporate innovation. In addition, we also further explore the impact mechanism of cross-listing to corporate innovation. The main findings are as follows: (1) Compared with the companies listed in Chinese mainland, the cross-listed ones put less R&D investment, while get more innovation output. That is to say, the cross-listing strategy is conducive to improve corporate innovation efficiency. The reason for this phenomenon is that innovation development needs the protection of a good institutional and market environment. When A+H share cross-listed enterprises face a more effective capital market environment, these enterprises will be more inclined to innovation projects and pay attention to the improvement of efficiency, so as to optimize the allocation of innovation resources and improve the efficiency of innovation investment. (2) Cross-listing affects corporate innovation from the following two aspects: corporate governance and financial costs. In terms of corporate governance, cross-listing mainly affects corporate innovation by improving investor protection, accounting information quality and investor attention; and in terms of financial costs, it mainly affects innovation by reducing financing constraints. (3) In the mechanism of cross listing′s impacts on innovation, investor protection, accounting information quality, investor attention and financing constraints have mediation effects about 60% all together, which could be considered as the main path for the impact of cross listing on corporate innovation.
    Based on the main conclusions, this paper puts forward some policy suggestions. Regulatory authorities could encourage mainland listed companies to list on Hong Kong Exchanges, could further develop the market and regulatory requirements in Chinese mainland when encouraging cross-listing, and could actively formulate relevant policies, make more detailed provisions on the financing system, further alleviate the financing problems of cross listed companies, and protect the interests of investors and enterprises to the maximum extent.
     This paper expands the relevant research on the economic consequences of cross-listing and the influencing factors of innovation. Previous studies on cross-listing mostly focused on motivations and market reactions, and there is still a lack of in-depth analysis on whether cross-listing affects corporate innovation. In addition, this paper also explores the mechanism of cross-listing on corporate innovation. It is found that investor protection, accounting information quality, investor attention and financing constraints are the main ways that cross-listing affects corporate innovation. This conclusion is of great significance for guiding the innovation practice of enterprises.

Key words: cross-listing, corporate innovation, corporate governance, cost of capital