Abstract: By statistical computation and RS/GIS method,the environmental risk factors,including hydrological characteristics of wetland,water pollution,land-use/cover and their evolution in lower reaches of the Weihe River,were analyzed.The results are as follows.(1) The quantities of the water and sand are changing dramatically in recent years,and their distribution with the decreasing tendency are not even.In flood season water from the Yellow River flows backward to the Weihe River,which relieves the threat resulted from the decreasing of water and sand supply,and reduces the risk for wetland brought by the changing mentioned above.(2) The degeneration of the hydrological environment of wetland lowers its purification capability,and increases its hydrological environment risk.(3) From 1989 to 2000,in the lower reaches of the Weihe River,the area of the wetland increasesd 12.96 km² with an annual increase rate of 2.7%,and there were 2.002km² and 0.94km² of wetland become bare and saline land,respectively.In addition,0.03 km² wetland was occupied by urban construction.(4) By some measures,such as strengthening lawmaking,fathering water pollution,reconstructing vegetation and enhancing management,environment safety and resources sustainable use will be come tuer.