Abstract:     Under the policy background of vigorously promoting overseas innovation investment and the increasingly frequent international environment of cross-border flow of innovation resources, Chinese enterprises pay more and more attention to global layout and technological innovation. Market competition and market structure have a far-reaching impact on the relationship between transnational operation and technological innovation. However, there are few studies on the combination of enterprise behavior and market environment. Therefore, we analyze the impact of transnational operations on the innovation efficiency of enterprises from the two dimensions of market competition and market structure, and provide new research perspectives in this field.
   In the international context of innovation resources, competition, cooperation, how to efficiently use the market environment to take into account transnational operations and technological innovation development, is a topic worth studying. Using the data of 472 listed companies with transnational operation behavior from 2008 to 2019, DEA Tobit model is used to test the influence of transnational operation on innovation efficiency of enterprises, and the regulation of market environment. 
    The conclusions of this paper can be drawn as follows: Firstly, transnational operations can provide external innovation resources and diversify the market risks, thereby ensuring continuous and sufficient R&D investment and improving innovation efficiency. This improvement is more significant among non-SOE, because SOE in China usually shoulder multiple economic and social functions, and may gradually produce and rely on a hot-bed effect, which will consume resources and inhibit the growth of performance, profitability and innovation efficiency. Therefore, the effect of multinational operations on innovation efficiency still exists but is relatively weak in SOE.
    Secondly, the market environment can be divided into two dimensions: market competition and market structure. On the one hand, market competition positively regulates the relationship between transnational operations and innovation efficiency, which is more significant in non-SOE. As an effective external governance mechanism, market competition can not only open up resource channels from the outside, create a better market environment for enterprises, but also stimulate the self-driving force and innovation enthusiasm of enterprises from the inside. On the other hand, the market structure negatively regulates the relationship between transnational operations and innovation efficiency, which is more significant in SOE. When measuring the market structure from the perspective of the supply chain structure, the higher the concentration of a supply chain, the stronger its dependence on upstream and downstream, and the weaker the bargaining power of the corporate. 
    Finally, mechanism studies have found that transnational operations not only improve innovation efficiency by increasing asset allocation and providing funds, but also selectively enhance innovation efficiency by enriching human resources. Transnational operations will increase investment in intangible assets and R&D equipment, and can also attract R&D personnel and senior executives with overseas backgrounds. The former can effectively promote innovation, while the latter can inhibit the growth of innovation efficiency. This is because too many senior executives with overseas backgrounds may lead to organizational redundancy and strategic deviation, increase internal communication costs and management conflicts, and produce a crowding out effect on innovation. After the robustness tests of instrumental variables and substitution variables, the research conclusions are still significantly established. In general, this research has certain guiding significance for companies to deeply integrate into globalization and improve the performance of transnational operations.

Key words: transnational operation, innovation efficiency, market competition, market structure