This study deals wi th the relation between algal biomass and 15 environmental factors such as w ater temperature (WT), suspend solids (SS), Secci-depth (SD), DO, COD, pH, NH₄-N, NO₂-N, NO₃-N, TN, PO₄-P, TP, Alkalinity (ALK) based on the monitoring data from 1992-1999 in Meiliang Bay, Lake Taihu.The stepwise multiple regression statistical method was used to calculate the relation between algal chlorophyll-a (Chla), total algal biomass (TB), Microcystis biomass (MB)and these environmental facto rs.The results show ed that WT and TP were the most significant related factors to TB while WT, NO₃-N and TN were the most significant related factors to MB.These can be used to predict the blue-g reen algal bloom in the bay.