Trace elements of Taihu Lake are detected and their characteristics and variation trends are analyzed. The upper-crust standardized values of trace elements show that the pattern of the sediment is different from that of the rock. The concentrations of heavy metals, especially As, Hg, Cu, Zn and Ni, are relatively high in northern Taihu Lake, which is the major polluted source of heavy metals. We discuss the enrichment of heavy metals based on the background values and evaluate the pollution degree using the geoaccumulation index. The chart of element enrichment shows that Ni, Pb and Cu have larger enrichment levels than others. Based on the data of 1987 and 2000, we have calculated the accumulation rates of heavy metals in sediments. It is found that most of heavy metals are accumulated in the past decade. By comparison of elements between rock, soil and sediment, we also conclude that most of trace elements in sediments depend on weathering and natural processes, and only heavy metals as we know are affected by human activity.