Abstract: Abstract: Determine evapotranspiration (ET) and its components is important for us to understand the influence of mulching on filed water consumption, to develop precision irrigation scheduling and to improve water use efficiency in the field. In this study, the net radiation, field soil evaporation and crop transpiration, crop growth and yield of film mulching (M) and non-mulching (NM) maize fields were measured in a continuous 2 years field experiment in the drip irrigation with mulching area of ??Northeast China. Net radiation was measured by two net radiometers in the center of every representative plot of the M and NM treatments at height of 50 cm above the canopy adjusted with the increase of plant height and 30 cm above ground. Soil evaporation was measured by micro-lysimeters made from polyvinyl chloride (PVC) tubes and it was weighed every day. Transpiration during the middle and late growth period was measured and scaled up from the sap flow rates. Transpiration of the whole growth period were calculated the by using the dual crop coefficient method with the adjusted medium-term basal crop coefficient from the FAO-56 manual. The medium-term basal crop coefficient were adjusted with the measured transpiration. The results showed that: The net radiation above the canopy of M treatment reduced by 7.7%, i.e. the energy available for evapotranspiration reduced. The net radiation under the canopy of M treatment reduced by 34.0%, i.e. the energy available for soil evaporation (Es) reduced. However, the net radiation absorption by the canopy of M treatment increased by 14.0% for crop transpiration (Tr). The film mulching could reduce the total amounts of evapotranspiration by 3.9%(5.2%. ET of M was 471.3mm in 2014, which was 5.2% lower than that of NM treatment (497.4 mm). In 2015, ET of M was 413.4 mm, 3.9% lower than that of NM treatment (430.0 mm). The film mulching had a significant effect on the water consumption distribution between Es and Tr. Total Esof the whole growth stage for M and NM treatments were 58.8 and 108.8 mm in 2014, 60.0 and 107.6 mm in 2015. Plastic mulching decreased Es by 44.7% and increased Tr by 7.8% in this area for the two years, comparing to those of NM treatments.The ratios of Es to ET in 2014 and 2015 were 12.5%(14.5% for the M treatment, and which were up to 21.7%(25.0% for the NM treatment. The ratios of Tr to ET were 85.5%(87.5% and 75%(78.3% for M and NM treatments, respectively. The plant height of maize, the stem diameter at 20 cm height above the ground, biomass at the maturity stage and the maximum leaf area index of treatment M were significantly higher than those of treatment NM by 7.1%, 5.8%, 4.8% and 1.7% in 2014 and 5.4%, 8.8%, 6.9% and 2.2% in 2015. The yield of M treatment increased by 5.9%(8.8%, and water use efficiency increased by 12.0%(13.1%. In summary, the film mulching reduced the total amount of ET in maize field by changing the canopy radiation energy distribution, and finally enhanced the plant growth, increased grain yield and water use efficiency in maize field with drip irrigation in this area.