The digital economy development promotes green transformation in China’s economy. Based on provincial-level data from 2011–2019, an ArcGIS spatial analysis is used to explore the spatial and temporal evolution patterns of the digital economy development and green economic efficiency. The digital economy development’s impact on the green economic efficiency is tested through fixed effect, mediation effect, and spatial Durbin models. The digital economy development and green economic efficiency increased during the study period. Spatial patterns of high-level areas spread to form “clusters” with surrounding areas. The digital economy development’s catalytic effect on the green economic efficiency holds after robustness and endogeneity tests. A heterogeneity analysis shows that the digital economy development promotes the green economic efficiency in the eastern and central regions; the impact on the western region is non-significant. Compared with industry digitalization, digital industrialization has a stronger promoting effect on the green economic efficiency. The digital economy development better facilitates the green economic efficiency in regions with high digital economy development levels and Big Data experimental areas. The digital economy development promotes green economic efficiency through human capital, industrial structure upgrading, and technological innovation; industrial structure upgrading has a stronger mediating effect, reaching 40%. The digital economy development facilitates the regional green economic efficiency and significantly promotes green economic efficiency in neighboring regions through spatial spillover effects.