Influence of FDI on China's Green Marine Economy

China attaches great importance to the protection of Marine resources, the development of Marine economy and the construction of a maritime power. FDI is highly concentrated in China's coastal areas and accompanied by space spillover, which affects the development speed and quality of Marine economy. Does FDI improve the efficiency of China's Marine green economy? Based on the panel data of 11 coastal provinces and cities in China from 2004 to 2020, the "efficiency evaluation system of Marine green economy" is constructed from the dual perspective of environmental constraints and resource conservation, considering the unexpected output and measuring the efficiency of Marine green economy with the ultra-efficiency SBM model. Then, under the geographical weight and economic geographical weight, the FDI spatial index is constructed to study its influence on the efficiency of Marine green economy. The results show that FDI space can improve the efficiency of Marine green economy in China. FDI has a negative effect on the efficiency of Marine green economy, but after considering the spatial factors, the FDI spatial index has a positive promotion effect on the improvement of the efficiency value, and the promotion effect is more significant under the weight of economic geography and space.