The Beijing-Tianjin-Hebei region has jointly built an open platform for internationalization, providing new opportunities for FDI inflows and the development of innovative activities. Based on the panel data of cities in the Beijing-Tianjin-Hebei region from 2011 to 2021, the role and mechanism of FDI in influencing independent innovation in the Beijing-Tianjin-Hebei region was examined. The conclusions of the study are as follows. The use of FDI in the Beijing-Tianjin-Hebei region has a significant promoting effect on its independent innovation ability, which is positively moderated by the number of higher education students, and has a nonlinear impact with the development of regional digital economy. The upgrading of industrial structure is one of the ways to use FDI to influence independent innovation in Beijing-Tianjin-Hebei. The results of regional heterogeneity show that the use of FDI in external regions has a greater promotion effect on independent innovation than in the central core functional area, and the results of annual heterogeneity show that with the implementation of the synergy strategy, the promotion effect of FDI on independent innovation capability in the Beijing-Tianjin-Hebei region has changed from insignificant to significant.