Abstract:This paper made empirical researches on the mechanism between regional innovation investment and innovation performance.Based on panel data of 31 provinces in our country from 2010 to 2021, this paper used panel regression and threshold model to study two issues. The first one was, whether the regional innovation investment had a positive impact on innovation performance in general; The second one was whether different levels of local government science and technology innovation support will affect the relationship between regional innovation investment and innovation performance, and whether there was an optimal level of local government science and technology innovation support. The results showed that regional innovation investment had a positive impact on innovation performance, and there was regional heterogeneity in the east, middle and west, with the highest correlation coefficient in the middle and the lowest in the west. Under different levels of local government science and technology innovation support, there was a significant double threshold effect between regional innovation input and innovation performance. The transfer efficiency of regional innovation investment to innovation performance was the highest in the middle support range. But at present our country 31 provinces local government science and technology innovation support were generally in the high level. Therefore, the policy recommendations were as follows, on the one hand, we should continue to insist on regional innovation investment and take into account the characteristics of regional heterogeneity; on the other hand, under the pressure of economic recovery, local governments should optimize and adjust the allocation of innovation resources, and pay more attention to transformation efficiency than the amount of regional innovation input just as previous.