Rapid development of mariculture supplied the demand of quality protein for human,meanwhile,also resulted in environmental degradation and ecological imbalance.For this reason,lots of maricultureecological models for improving cultured environment were suggested.Among them,seaweeds/macroalgae were introduced into the system and produced environmental effects.However,macroalgal effect was only restricted in water column,with no effect to improve quality of sediment.This article investigated three-dimensional effects of improving environmental quality by introducing benthos and seaweed into the system.Different stocking densities of benthos(Perinereis aibuhitensis)were introduced into the cultured systems that only had fish(F)or fish seaweed(Gracilaria lichenoides)to investigate the effect of benthos on removing POM of sediment and the most optimal density of benthos to build an integrated mariculture system(IMCS).The results showed that the benthos made remarkable effect of reducing POM in sediments.Compared with the system that only has fish(F model),the contents of nitrogen(N)and phosphorus(P)in sediments decreased by 9.59%-10.47% and 7.11%-8.18%,respectively in the models of FP(fish benthos)and FGP(fish seaweed benthos).And the stocking density of benthos had a significant impact on the removal of POM in the sediment.The models with the densities of 22.5 kg/hm² and 30 kg/hm² had better environmental benefits than the one with 15 kg/hm²,and there were no differences between the two high densities models.Considering this two treatments’ remediation effects and culture benefits,22.5 kg/hm² of benthos’ density can promote the culture benefit and improve the sediment environment.