To explore the effects of different culture models on growth performance and quality of Chinese mitten crab (Eriocheir sinensis),and the aquaculture water environment,and to estimate the optimum stocking density of crab culture by using natural feed resources in a shallow macrophyte-dominated lake,the Chinese mitten crabs have been raised at different stocking densities as 3000,6000,9000 ind./ha,respectively,in net-pen aquaculture area in the East Lake Taihu by feeding aquatic weeds and snails, and/or by feeding exogenous fish and corn as control for each treatment.The results showed that all crabs from each treatment group achieved 150 g in body weight,but their body size and flesh increment were significantly lower than those of control group fed with exogenous diets.There was no significant difference in yield between the lowest density group (3000 ind./ha) and its control group,while the yields in the other two groups were significantly lower than their control groups.Moreover,the recapture rate of the lowest density group was significantly lower than its control group,while that of the other two higher density groups didn't show difference when compared with their control groups.Results also indicated that the water quality in the treatment area was better than that in the control area with exogenous feed,and the TP contents were significantly lower.It was revealed that exogenous feeding might be responsible for higher levels of nitrogen and phosphorus in aquaculture water and water eutrophication.On the contrary,feeding natural aquatic weeds and snails could effectively handle the overgrowth of hydrophytes.Meanwhile,nutrient of nitrogen and phosphorus could be removed from aquaculture water by harvesting the Chinese mitten crabs,which will play an effective role both on water purification and aquatic ecological restoration.When both ecological effects and economic benefits were considered, it is suggested that the optimum stocking density of Chinese mitten crab aquaculture in shallow macrophyte-dominated lakes should be 6000 ind./ha when natural feed resources are utilized.