Abstract: In order to explore the impact of customer concentration on the supply of commercial credit, and the role of cost stickiness in regulating its relationship, the data of China’ s Shanghai and Shenzhen A-share manufacturing listed companies from 2009 to 2018 was taken as a research sample, customer concentration was selected as a variable reflecting customer relationships, its impact on commercial credit supply was analyzed and investigated. And how different cost stickiness affects the relationship between customer concentration and commercial credit supply was further examined. The results show that there is a significant inverted U-shaped relationship between customer concentration and commercial credit supply; Compared with weak-cost-sticky companies, the sensitivity of the inverted U-shaped relationship between customer concentration and commercial credit supply of companies with strong cost-stickiness even stronger, cost stickiness has a positive regulatory effect on the inverted U-shaped relationship between customer concentration and commercial credit supply.