Some physical and chemical characteristics of sediment in West Lake.Hengzhou are dis-cussed in this artide Preeipitation trial test shows that particles with diameter between 0.067mman d 0.0029mm constitute 80.6 percent of the total sediment in West Lake, end particles with diameter below 0.0029mm constitute 4.3 percent of the total, and suspended particlas can appar-endy affect the diaphaneity of water.Sediment in West Lake is situated in a neutral an aerobic sta-tus(pH=6 60-7.40;Eh=-3mV to 167mV), Do on the interface between water and sedi-ment approximately equals lmg/L Biology production number(BPN=0.4836)and IG-totalnitrogen ratio(IG/TN=22.54-30.71)of sediment show that West Lake has a characteristic of both hyperproducfive and high humans content.Principal Component Analysis(based on sediment parameters)demonstrates that the precursor of West Lake sediment is bog, and sediment in Xiao-nan Lake is apparan tiy different together areas due to the diversion operation.