Since its traditional comparative advantages are on the wane, China should use digital economy to enhance its competitiveness of manufacturing export. Based on microscopic data of various regions in China from 2013 to 2020, this paper studies the relationship between digital economy and China’s competitiveness of manufacturing export, the internal mechanism of their influence, and the boundary conditions for the establishment of the relationship between digital economy and competitiveness of manufacturing export. Our conclusions include that: there is a significant positive spatial correlation between digital economy and export competitiveness; digital economy can not only enhance the export competitiveness of the region, but also have a positive impact on that of adjacent regions; innovation efficiency, the accumulation of human capital and synergistic agglomeration exerts a mediating effect when digital economy impacts China’s export competitiveness; and with the share of import trade as the threshold variable, the facilitating effect of digital economy on the export competitiveness of the western region is lower than that of the eastern region before the threshold, but significantly higher than that of the eastern , central and northeastern regions as well as the whole country after the threshold. Therefore, China should vigorously promote the construction of new digital infrastructure in the western region, and give full play to the role of new digital infrastructure in promoting trade upgrade. Through the improvement of human capital quality, the centralized development of digital economy and the overall improvement of innovation efficiency, we should gradually improve the international competitiveness of China’s export enterprises.