Using the merged China Customs import and export database and industrial enterprise database from 2010 to 2016 to calculate the quality at the enterprise product annual level, An econometric model is constructed to empirically test the impact of China''s economic agglomeration on the upgrading of enterprise product quality. The results show that the improvement of economic agglomeration helps to improve the product quality of Chinese enterprises. By gathering in specific areas and getting closer to labor, suppliers, consumers and transportation hubs, enterprises reduce the cost of employment, logistics and promotion, So that enterprises have more resources to upgrade product quality. At the same time, it clarifies the mechanism of economic agglomeration affecting product quality upgrading. The efficiency improvement and marginal cost reduction brought by agglomeration promote product quality upgrading.