The pilot policy of patent pledge financing can alleviate the financing constraints of SMEs and even the lack of innovation investment, but the policy mechanism remains unclear. Choosing the biomedical industry with important strategic role and strong policy guidance for China''s economic development , based on the data of Shanghai and Shenzhen A-share bio-pharmaceutical listed companies from 2011 to 2020, as a quasi-natural experiment, the pilot cities of patent pledge financing were identified, and using the double difference method, this paper analyzes the influence of the pilot policy of patent pledge financing on the performance of biomedical enterprises，and the mediating role of technological innovation between the two. It is found that: firstly, the pilot policy of patent pledge financing can directly influence the performance of biomedical enterprises, and through promoting technological innovation to play partial mediation, that is, the pilot policy of patent pledge financing can improve the performance standard of biomedical enterprises through technological innovation. Secondly, further heterogeneity test shows that the pilot policy of patent pledge financing has a higher impact on the performance level of non-state-owned biopharmaceutical enterprises and large biopharmaceutical enterprises. Thirdly, further analysis shows that the proportion of tangible assets has no obvious effect on the performance of enterprises. The research conclusion not only provides a certain theoretical basis for the current debate about the effectiveness of the patent pledge financing pilot policy in China, but also puts forward some suggestions on how to implement the patent pledge financing pilot policy in China accurately.