According to the date of water quality collected from Taihu Lake in 1987-1988,seventeen indexes in three pollution types of organic matter,hygienic index,nutrients,toxic and harmful materials were evaluated by means of a systematic dynamic cluster analysis.The spatial distribution of pollution index in Taihu Lake and the differences of index character were obtained,and the results revealed three type pollution models and their distribution status.This paper offers an important information for further improving water quality and controlling water pollution of Taihu Lake.