Taking the implementation of the Property Law in 2007 as an exogenous event, this paper constructs a difference-in-difference model and empirically tests the impact of reform of property right system on the innovation investment efficiency of listed companies in China, with the listed companies in China from 2003 to 2011 as the research object. The research finds that the reform of property right system improves the innovation investment efficiency of listed companies in China, but the improvement of innovation efficiency is mainly achieved through application-oriented innovation. For development-oriented innovation, the promotion effect of Property Law is not significant. However, differences in the scale of equity financing have different effects on the relationship between property right protection and innovation efficiency. Specifically, compared with companies with smaller scale of equity financing, in the companies with larger scale of equity financing,the improvement of the level of development-oriented innovation is more significant under the background of strengthening the protection of property rights.