Zhang Zidao Island became the largest base for mariculture of Japanese scallop Patinopecten yessoensis from 1995. Total culture areas of the scallops are about 47 000 hm2, annual yields arrived at 40 000 t in this area. In order to keep the aquaculture industry sustainability and to utilize the limited water areas reasonably and sufficiently, the carrying capacity of the scallop for Zhang Zidao Island was assessed by the methods of food limited indexes. Environment factors (tide change, water movement), chlorophyll a and primary production were measured. The clearance rates of different size scallop Patinopecten yessoensis were determined with flowthrough system and its population shell heightfrequency distributions of the scallop within the areas were measured in July and October. Results showed the average concentration of chlorophyll a was at the range of 1.23-2.85 mg·m-3［with the annual average of (1.78±0.57) mg·m-3］, primary production was (76.6±41.9) mg C·m-2·d-1. The average clearance rate of the scallop was (0.55±0.25) L·h-1·ind-1. Based on the above investigated data and annual yields and mariculture areas etc, food limited indexes (clearance efficiency, filtration pressure and regulation ratio) were calculated and the ecological carrying capacity and production carrying capacity were assessed. Both food limited indexes: filtration pressure and regulation ratio were between 0.05 and 1.0, clearance efficiency was lower than 0.05, which mean the suspended particle organic materials mainly come from the water exchange. Results showed that if the total water volume is used by the cultivated scallops, current cultured biomass of the scallop in Zhang Zidao Island was at the level of ecological carrying capacity (total individual is 12.8×108), which means at current status, the scallop cultivated behaviour has not great influence on the environment and there will be 20 times developing potential to get the level of production carrying capacity, the potential annual yield will be 32×108 individual.