China's promotion of the "dual circulation" of the economy is to complete the mutual promotion and integration of domestic and international economic cycles on the basis of adhering to the domestic cycle. In this context, the importance of corporate innovation capabilities has become more prominent. The article selects the "One Belt One Road" initiative as the policy measurement event for trade liberalization, uses the 2009-2019 A-share listed companies as the research sample, and uses the Differences-in-Differences method to examine the actual impact of the "One Belt One Road" initiative on the innovation of Chinese enterprises, and at the same time in-depth analysis the role of financing constraints in the above influence reveals the internal mechanism of enterprise innovation. The results show that the country's adherence to high-quality opening to the outside world and the significant improvement of enterprises' innovation capabilities through trade liberalization will help promote the formation of a new domestic and international dual-cycle development pattern, and this effect will be achieved by alleviating corporate financing constraints. Further analysis of the heterogeneity of enterprises found that the innovation capabilities of private enterprises, large-scale enterprises, low-tech enterprises, enterprises with separation of two posts, and enterprises in the eastern region have improved significantly. This research conclusion is helpful to understand the positive benefits of the “One Belt One Road” initiative, and provides enlightenment for the government to further improve policies and Chinese enterprises to strengthen the use of policies under the new pattern of “dual circulation” economic development.