Abstract:The intertidal zone between the land and the sea was impacted seriously by all kinds of human activities. Influences of environment conditions and pollution can be shown by the macrozoobenthic community and species distributed in the intertidal zone. With rapid economic development and overexploiting, Yueqing Bay (a semi-enclosed bay) is seriously threaten by human activities; such as industrial and agricultural discharges, aquaculture ponds and land reclamation. Resultant effects are: 1) the landscapes of intertidal regions are damaged, 2) polluted water and sediments, and, 3) recession of the marcozoobenthic community. Five different stations were investigated in September 2006 and May 2007 to assess impacts of human activities on intertidal macrozoobenthic community distribution patterns in Yueqing Bay. One hundred and thirteen species were identified, including 40 species of molluscs, 25 of polychetes, 24 of carapace, 9 of echinoderm, and 15 others. The number of species fluctuated across seasons. The 81 species in Autumn exceeded the 68 species in Spring. However, the average macrozoobenthic biomass and inhabit density in spring were (91.90±59.14)g/m2 and (1541±1261.41)ind./m2, respectively; which were higher than those in Autumn; these being (29.20±22.20)g/m2 and (201±52.97)ind./m2, respectively. Dominant species were juveniles of Potamocorbula ustulata (Reeve), Moerella iridescens (Benson), Retusa (Coelophysis) boenensis (A.Adams), Assiminea latericea (H. et A.Adams) in Spring; and, Assiminea brevicula, Moerella iridescens (Benson), Ilyoplax tansuiensis Sakai, Diopatra neapolitana (Delle Chiaje) in Autumn. The results indicate that the functional status of the macrozoobenthic community changes with seasons. The biodiversity index varied from 2.34 to 3.31, the average being 2.85±0.35. The index of Margalef's species richness was from 3.02 to 6.42, the average being 4.29±1.10. The Pielou's evenness was from 0.46 to 0.73, the average being 0.62±0.09. Upon analysis of the macrozoobenthic community structure by ABC curve, only the Huanghua section had not been affected in Spring. According to hierarchical clustering analysis and MDS diagrams, community stability is bad in Yueqing Bay. The community with more than 40% of similarity could be clustered into three groups; the first was all of the sections in Spring, the second was sections including Huwu, Ximen Island, Nantang and Wengyang in Autumn, and, the third is the Huanghua section in Autumn. The data analyzed by MDS were consistent with the results of the hierarchical clustering analysis. The above mentioned results show that the structure of macrozoobenthic community had suffered moderate disturbance with the consequence of poor stability in Yueqing Bay. Compared to previous research, biomass and density were significantly decreased, and the dominant species changed from large to small ones; such as Cyclina sinensis (Gmelin), Sinonovacula constricta (Lamarck) and Cultellus scalprum (Gould) being replaced by Retusa (Coelophysis) boenensis (A.Adams), Assiminea latericea H. et A.Adams, and Assiminea brevicula. Changed variety of the macrozoobenthic community from its original type to the secondary type reflects the adverse impact of human activities that include excessive exploitation, habitat degradation, coastal engineering and pond farming.