This paper presents the results of ecological study of the macrobenthic fauna in the Huanghe River estuary and adjacent waters. The materials for study were collected during eight cruises in April-November 1984. The species composition and distribution of biomass and density was described and discussed. Relative abundance of Echinodermata is higher in area northern to the river mouth, but that of Mollusca is higher in the southern area. Polychaeta was found everywhere in the explored region, but Crustacea was abundantly found in area northern to the river mouth. The distribution of biomass and density is extremely uneven, but the areas of high biomass and high density were basically similar, both in Laizhou Bay. The highest record of biomass occured in July, being ?X＝ 50.76g m-2, but the lowest was in November, being ?X＝ 25.83g m-2. The highest record of density was in November, being ?X＝622 ind. m-2, but the lowest in August, being ?X＝304 ind. m-2. Dominant group of the benthic fauna in this region was Mollusca, particularly Musculus senhonsei. In this paper, the seasonal change in abundance (biomass and density) of Musculus senhonsei was described.