The ecology of marine meiobenthos was studied in an organically polluted intertidal beach of the eastern part of Qingdao Bay from April 1991 to March 1992.Based on the characteristics of meiofauna and environmental factors (e.g. DO2, PH,Eh and sulfide in pore water or sediment), the whole beach can be divided into four ecological zones: (1) grossly polluted zone, (2)polluted zone, (3) semipolluted zone,and (4) transitory zone. Compared with former studies here, it can be concluded that the polluted area has been greatly reduced after the shut-down of the main sewage outfall. Free-living marine nematode is the predominant group of meiobenthos in this polluted environment. Its density ranges from 36.7 in /10cm2 to 10298.6 in./10 cm2, and its relative abundance reaches 98.41% all over the transect. Of all the 45 species of nematodes, Metoncholaimus moles is the predominant species. Its population and the total density of nematodes show a clear and seasonally steady distribution pattern along the pollution gradient. Because of the strong influence of season and sediment type, the diversity of nematode communities and the hotly argued N/C (the ratio of nematodes to copepods) cannot serve as a sensitive pollution indicator.Cluster analysis of nematode communities shows that the species composition of nematodes exhibits a clear and seasonally steady distribution pattern along the pollution gradient and is strongly influenced by the pollution impact, and that there is an apparent species composition difference between the polluted transect and the control transects. Because of the short life span of marine nematodes, the species composition of nematode communities (compared to macrofuana) is a more sensitive indicator of the real extent of pollution impact.