Abstract:R D activity is a high-risk and long-term investment, which are faced with the principal-agent problem between shareholders and managers for the listed companies. Based on the semi-natural experiment of margin trader, using DID regression method and PSM-DID method, this paper examines the effect of margin trading on the R D expenditure of Chinese listed companies. The results show that margin trading will raise R D expenditure. The results are still stable when considering the size of margin trading. Finally, we further test the influence channel of financing margin on R D, and the result shows that the financing margin will improve the company"s R D expenditure by reducing the information asymmetry of the listed firms" stock.