This paper takes the A-share listed company from 2012 to 2016 as an example to study the impact of the implementation of new environmental protection law on enterprises' technological innovation investment by means of the PSM-DID model.The results show that after the implementation of the new environmental protection law, the technological innovation investment of affected companies has increased, but the results are not significant. Further research explores the reasons and found that besides the time-delay characteristics of the new environmental protection law, the company did not make timely adjustments to the major aspects of the company's technological innovation, such as the capital structure, governance structure, and incentive programs of the company under the implementation environment of the new environmental protection law. Therefore, the mandatory role of the environmental protection law cannot affect the technological innovation of the enterprise quickly and effectively.