Investigation of macrozoobenthos was carried out in East Lake Dongting Reserves in September, 2001.All total, 51 taxa were identified from thirty-two sampling sites, of which, 18 oligchaetes, 15 mollusks, 14 insects and 4 other forms.Mollusks constituted the most dominant group and accounted for more than 70% of the total a-bundance.Among which, four gastropods, Alocinma longicornis, Bellamya aeruginosa, Parafossarulus sinensis, P.striatulus and one oligochaete Branchiura sowerbyi were the dominant species.The richness and three biodiversity index values ((Margalef, Simpson and Shannon) per site were 6.3, 1.38, 4.05 and 1.47, respectively.Assemblages were composed mainly of scrapers (66.7%) and collector-gatherers (19.9%), and to a lesser extent to other functional feeding groups.The investigation data were compiled and a GIS database of macrozoobenthos was established.A vector boundary map of the lake was digitized and georeferenced, then used to introduce sampling sites.Under the support of GIS software Arcview 3.2 and the relative extension modules (Spatial Analyst Extension 2.0 and Kringing Interpolator Extension 3.22 SA), the GIS database was employed to simulate spacial distribution patterns of parameters of macrozoobenthos and Hilsenhoff biotic index (BI).The simulation process was based on the principle of Kringing interpolation technique.The simulated results were stored as Arcview Grid format with a grid precision of 20m.The higher distributional pattern of main groups and five dominated species were overlapped based on the 2-4 times as mean abundance, and the 16 physical-chemical parameters were collected in these higher distributional regions.The simulated patterns of macrozoobenthos showed that these patterns were relatively high spatial heterogeneity, and distributions of most parameters of macrozoobenthos had usually 2—4 high value distributed zones in the whole lake.The oligochaete pattern showed basically no overlapping with two other groups, and mainly distributed in deeper region.ANOVA detected water depth was the key factor influencing the distribution patterns of macrozoobenthos, and SO₄^2- mainly controlling the pattern of oligochaete, and hardness the main factor affecting mollusks.The average of BI (8.18) revealed the Reserves endured higher organic pollution.