Using 64 stations water quality data collected in Taihu Lake, the spatial distribution of water color parameters and euphotic depth was analyzed, and the potential effect on hygrophyte photosynthesis was discussed. The result showed that the most variation was found for Chl a concentration, the value varies from 1.67 microg x L(-1) to 159.94 microg x L(-1), with the standard deviation of 41.03 mg x L(-1). The high Chl a concentration was recorded in Meiliang Bay, Zhushan Lake, Jiapu port and Xiaomei port with obviously spatial variation and compressive isoclines. The spatial variation of total suspended matter (TSM) concentration was lower than that of Chl a with a standard deviation of 31.63 mg x L(-1), and the concentration varies from 6.47 mg x L(-1) to 143.47 mg x L(-1). The high value was found in the area near Dapu port and Xiaomei port, with obviously spatial variation and compressive isoclines. No markedly spatial variation was found for colored dissolved organic matter (CDOM) in the whole lake. Euphotic depth was influenced by TSM and Chl a concentrations, while the influence by TSM was greater than that by Chl a. Therefore, the characteristics of spatial distribution for euphotic depth are reverse with TSM.