How Does Digital Economy Drive Export Trade of Chinese Cities?—Based on the Perspective of Influence Mechanism Analysis and Threshold Effect

Driven by the digital transformation of global value chains and the digital economy strategy outlined in China’s 14th Five-Year Plan, international trade competition is increasingly centered on digital technology ecosystems. This study addresses the gap in existing research that often overlooks the critical role of cities as key nodes in digital technology and global value chains, as well as the mechanisms through which the digital economy influences urban export trade. Using panel data from 273 prefecture-level Chinese cities between 2006 and 2022, we apply fixed effects, mediation, and multiple threshold regression models to analyze the mechanisms and nonlinear effects of the digital economy on urban export performance. Results show that the digital economy significantly facilitates urban export trade, with its marginal impact moderated by regional development levels and factor endowment structures. Eastern and central cities exhibit stronger export-driving effects, benefiting from resource agglomeration. Technological innovation and human capital accumulation are identified as the main transmission channels through which the digital economy promotes export upgrading. Additionally, the relationship between digital economy development and export trade demonstrates significant nonlinear characteristics across different regional economic development stages. The study emphasizes bridging the regional digital divide and enhancing technological innovation and human capital efficiency to drive digital transformation and boost urban export vitality.