Based on the sample data of Chinese listed companies, this paper finds that the increase in customer concentration significantly reduces the level of enterprise employment. The research results are robust to a series of tests. Further analysis shows that the increase of financing constraints, the increase of enterprise risk and the decrease of profitability are the mechanism of customer concentration affecting enterprise employment. In addition, the negative correlation between customer concentration and enterprise employment is stronger for enterprises with small size, fierce industry competition, and increasing economic policy uncertainty.