Abstract: The construction of a social credit system can improve the urban business environment in China, and thus potentially affect inter-firm specialization by influencing their financing and transaction behaviors. This paper selects a sample of industrial enterprises in 238 prefecture-level cities in China from 2000 to 2013, takes the policy of restricting luxury consumption in 2010 as a policy shock, and uses the data of the defaulters released by the Supreme People’s Court to construct a difference-in-differences (DID) model to explore the impact of social credit system construction on the specialization among manufacturing enterprises in China and analyze the main mechanism. The results are as follows. First, the improvement in social credit system construction can reduce the transaction cost and financing cost of enterprises, and then promote the specialization among enterprises. Second, the credit system construction has a greater impact on the specialization among private enterprises and small enterprises. Third, further research shows that the improvement of the social credit system reduces the imported intermediate inputs by enterprises and provides endogenous impetus for further realizing the new development paradigm with domestic circulation being the mainstay.