Abstract: Based on the measured data,annual water consumptions are estimated for different land useing types by applying evaporation coefficient method,and the ecological water use is analyzed in Weiganhe river plain oasis The results show that: (1)The water consumption for farm field and forest land,grassy marsh land and low lying land,waste land with sparse vege tations,waste land without vegetat ions are 947-1 026 mm,791-845 mm,308-415 mm,137-172 mm respectively; (2)The evaporation coefficient are 0.83-0.86,0.68-0.72,0.27-0.35,0.12-0.15 respectively;And(3)the amount of ecological water use is 11.8 to 13.7×10⁸m³,which accounts for 45 to 49% of sum of irrigated water,groundwater recharge and precipitat ion The results can provide the important scient ific basis for rational water resources allocation in the plain oasis is northwestern China.