Abstract: Evapotranspiration (ET) and transpiration (TR) of Sueade corniculata community were measured using artificial lysimeters in plant growing season in Songnen grassland. The climate data, including air temperature, air relative humidity, solar radiation, wind speed, soil moisture and plant water storage were simultaneously recorded. The results showed that the ET and Tr of Suaeda corniculata community varied significantly in different month. The diurnal variations of Tr had close relation with radiation, air temperature, relative humidity and wind speed. Solar radiation played a leading rote. The precipitation, ET, soil water storage and canopy water storage were main parts of soil-vegetation-air water flow system in Songnen grassland. In the whole growing season the water deficits of Suaeda corniculata community was not serious (6.3mm), but it changed significantly among months, the water deficits in June was serious (30.1mm).