Abstract: The port areas in Damen Island, Xiaomen Island, and Zhuangyuan'ao Island in the Oujiang River estuary are important parts of Wenzhou Port, Zhejiang, and are important areas of marine economy in Wenzhou City. Based on the coastline exploitation intensity, bathymetric topography condition, wave dynamic environment, seabed erosion and siltation risk, and seawater eutrophication in the port area, the geological resources and environmental carrying capacity of the port areas were comprehensively analyzed and evaluated in three aspects of coastline resource supply capacity, geological condition support capacity, and environmental carrying capacity. Data were collected in 2019 and earlier. Results show that the geological resources and environmental carrying capacity of the port areas was between 1.6 and 2.4, belonging to the higher range of the critical range of carrying capacity. The resource carrying capacity of Xiaomen Island was the lowest due to its low supply capacity of natural coastline resource and weak environmental carrying capacity; that of Damen Island was the highest and the water depth and terrain condition were the main limiting factors; and that of Zhuangyuan'ao Island ws in the middle, and the constraint was the supply capacity of natural coastline.