The progression of the social credit system is crucial for fostering enterprise innovation and elevating the quality of economic development. Based on the quasi-natural experiment of establishing demonstration cities for the social credit system, this study delves into whether the construction of a social credit system can indeed foster enterprise innovation. Our findings indicate that the establishment of demonstration cities for social credit system promotes enterprise innovation and improves the quality of innovation. Furthermore, mechanism test shows that it alleviates financing constraints faced by enterprises, leading to an increase in the scale and maturity of corporate loans, ultimately fostering corporate innovation. Further analysis of heterogeneity highlights that this positive impact is particularly evident in non-state-owned enterprises and those facing severe financing constraints. These findings present insights that the pivotal role of informal institutions, such as the social credit system, in facilitating the upgrading of industrial structures and augmenting the quality of economic development.