Abstract: In order to investigate the application of eddy covariance method, an experiment was carried out to evaluate the measurement of banana tree evapotranspiration in a large-size screen house with length, width and height of 352 m, 228 m and 6 m in June, 2005. Latent heat and sensible heat inside the screen house were measured using the eddy covariance method. Net radiations above banana canopy, changes of soil heat flux and soil heat storage were also measured using a meteorological system. The results show that total energy measured by eddy covariance system is same to the energy measured by meteorological system, which means the eddy covariance method can be directly used to measure the banana tree evapotranspiration (i.e the latent heat flux). In the experiment (from Jun 7 to 21, 2005), the banana tree evapotranspiration inside the screen house measured using the eddy covariance method ranged of 4.83－ 6.50 mm/d. Considering the relative constant meteorological condition from April to October every year, the measured banana tree evapotranspiration can be used to guide the irrigation of banana plants cultivated in screen houses in this region.