Abstract: Marine ecological security is the fundamental guarantee for the harmonious coexistence between humans and the ocean, as well as for achieving the sustainable development of the marine economy. Based on data from 2010 to 2021, the marine ecological security index of the Bohai Rim region was calculated by constructing an indicator system and the InVEST model, assessing its spatiotemporal evolution, and analyzing influencing factors and their spatial heterogeneity using the GTWR model. The results show that: ① The marine ecological security status of the Bohai Rim region has shown a phased improvement, rising from a relatively safe level to a very safe level. ② The ecological security level exhibits a spatial pattern of "higher in the east and west, lower in the central and south," with significant regional differences. ③ The GTWR model indicates that the area of coastal wetlands is a key positive driving factor; the proportion of marine science and technology professionals and urbanization progress have a significant impact on Shandong Province, while Tianjin is more influenced by the area of coastal wetlands and the urban air quality compliance rate.