Abstract: To analyze the hydrochemical types and the degree of heavy metal pollution in surface water of Amu Darya Basin, the water chemical parameters and the concentration of trace metals in the basin were studied. Results showed that the hydrochemical types and metal concentrations of surface water in the study area displayed significant spatial variations. Ca-HCO3 type (type I), with the lowest metal concentrations, was found near the mountain-pass, and controlled by rock weathering and atmospheric precipitation. While the Ca-Mg-Cl-, Na-SO4-Cl-, and Na-Cl types (type III), with the highest metal concentrations, distributed in the estuary or near urban and were dominated by evaporative crystallization. The Ca-Mg-SO4 type (type II) was observed in the middle and lower reaches of rivers, and dominated by rock weathering. Furthermore, by using the method of Nemerow index, the comprehensive pollution degree of heavy metals (As, Hg, Cd, Pb, Cr, Cu) in surface water was evaluated. The Pn mean values of type I and type II surface water were 0.28 and 0.18, respectively, indicating the safety level. However, the Pn mean value of type III was close to 0.7, which was significantly higher than that of others, and the values of Pn were greater than 1 in some water samples of type III, indicating relatively heavy pollution. The results of risk assessment had a good consistency with the spatial distribution of hydrochemical types, which were affected to varying degrees by human activities in this studied area. In general, the level of heavy metal pollution in surface water of Amu Darya Basin is relatively low, suggesting low risk.