Abstract: The present study was conducted to evaluate the effects of formulated diet(FD) and trash fish diet(TFD) on mud crab,Scylla paramamosain in integrated multi-trophic seawater pond system,while the feeding trial lasted 5 months.The results showed that there were no significant differences among the average body weight,hepatopancreas index and gonadosomatic index of S. paramamosain randomly selected from two dietary treatments(P>0.05). The crude protein content of muscle in crabs fed with FD was significantly higher than that of in TFD(P<0.05). The protease activity of crabs in FD pond was higher than that of in TFD pond,while the stomach amylase activity was significantly lower(P<0.05). The trypsin activity in gut was higher of crabs fed with TFD(P<0.05). The water quality indexes including NH₃^--N,NO₂^--N,NO₃^--N,DRP and TOC in TFD pond were high than those of in FD pond(P>0.05). At the genus level,the relative abundance of Marivitaa and other six taxa were significant higher in water of TFD pond(P<0.05), while the relative abundance of Geothermobacter and other eight taxa in sediment samples were higher in TFD pond(P<0.05). The total production(crab+shrimp+shellfish) and profit in FD pond were 374 kg and 6 210 yuan per 667,respectively,increasing by 5.9% and 42.6% than those of in TFD pond.In general,the formulated diet was determined to be more ecologically and economically sustainable than the trash fish diet for mud crab in the present aquaculture system.