Abstract: Sedimentation rates,element concentrations and grain size distribution of cores MS and DLS sediments from western Taihu Lake are investigated,which represent the sediment characters of north and south western Taihu Lake.According to ¹³⁷Cs dating,the average modern sedimentation rates of cores MS and DLS are 1.7 mm/a and 0.9 mm/a respectively.The geochemistry evolutional history of western Taihu Lake since 1920s' is studied on the basis of analyzing geochemical characteristics of sediments from core MS and DLS. The chemical elements in the sediments were from natural sources before 1940s' and some heavy metals and nutrients have been polluted due to human activities ever since.Pb,Zn,Mn,Ni,As and Hg are the main pollution heavy metals,which have different pollution history and pollution degree. Hg pollution began in the early 1940s' in north western Taihu Lake sediments,while in the south western Taihu Lake,it didn't begin to accumulate until the late 1980s' along with Mn,Ni and As.Pb,Zn,Ni,Mn and As pollution began in late 1970s' in north western Taihu Lake sediments and in the south western Taihu Lake Pb,Zn pollution also began.The concentration of TP in the north western Taihu Lake increased since early 1940s' because of the domestic wastewater,while that high concentration during 1940s' to 1970s' in the south western Taihu Lake might have a correlation with the chemical properties of phosphorous.The concentration of TN and TOC increased since late 1970s' both in north and south of the western Taihu Lake indicated the input of outsource organic matters,and the increased TN also related to the increased use of agricultural chemical fertilizer since late 1970s'. The higher concentration of TN and TP have close correlations with eutrophication of Taihu Lake.The pollution history recorded by sediments' geochemical proxies is correspondent with the economy development of Taihu Lake drainage basin.