Abstract: This paper presents the result of ecological studies of the macro-benthic fauna in the Changjiang River estuary and adjacent waters. The materialsfor study were collected in four cruises during 1982-1983. The composition anddistribution of species and density was described and discussed. Relative abundance of Echinodermata is in the area northern to the rivermouth. Poly-chaeta was found everywhere in the surveyed region, but Crustaceawas found abundant in the area northern to the river mouth. The distribution of bio-mass and density is extremely uneven, but both of high biomass and high density were basically similar, in the area northen to Changjiang River estuary. The hi-ghest record of biomass occured in August, being X=23.27gm^-2, but the lowest inFebruary, being X=10.09gm^-2. The highest record of density was in August,being X=84.8ind. m^-2, but the lowest in February, being X=20.1ind.m^-2. In thispaper, the seasonal change in abundance (biomass and density) of Xenophthalmuspinnotheroides was described too