In the research, element concentrations were investigated for 23 deposit samples collected from 8 rivers in Lanzhou urban area. Results indicate that enrichment factor values of Cl, S, P, Bi, Cr, Cu, Pb, Sn, U, W, Zn are all bigger than 2. Analysis of sediment enrichment factor shows a high pollution statue at downstream of Shuimo River and Yuer River. At certain extent, these elements come from artificial factors. The contribution of anthropogenic activities can be divided into 3 types: first is domestic sewage discharge and rain erosion on the ground or the street, and second is industrial pollution such as metallurgical industry, electro-deposition, and third is contribution of elements in soil of sierozem which is a major soil type in local area. Pearson correlation analysis between elements and grain size of river sediment indicates that pollutant always is rich in fine particles.