Evapotranspiration(ET) and transpiration(Tr) of Puccinellia tenuiflora and Puccinellia chinamopensis communities were recorded by using artificial lysimeters in growing season in Songnen grassland,together with climate data,such as air temperature,air relative humidity,radiation,wind speed,soil moisture and canopy water storage.The results show that the ET and Tr of each community varied significantly in different months,the ET and Tr of two communities were different in the same month.The d...