As a sensor and amplifier of global climate change， the hydrological process of the Qinghai-Tibet Plateau is a hot topic at present. Among them， evapotranspiration is the most difficult component in the hydrological cycle of the Qinghai-Tibet Plateau. Based on the observation data of vorticity system， Lysimeter and meteorological observation system in the Fenghuoshan area in the hinterland of the Qinghai-Tibet Plateau， the actual evapotranspiration in the growing season of the Fenghuoshan area in 2019 was evaluated by means of vorticity correlation method， lysimeter measurement and FAO56 Penman-Monteith formula. The results showed that： in Fenghuoshan area of Qinghai-Tibet Plateau， the crop coefficients of early， middle and late growing season were 0.93， 1.11 and 1.14， respectively； the actual evapotranspiration values obtained by the three methods were basically similar. The evapotranspiration in growing season was （495.00±21.69） mm， which was greater than 377.89 mm of precipitation in the same period； The results showed that the daily mean of evapotranspiration in Fenghuoshan area was （2.70±0.12） mm in the growing season， and the daily mean value of evapotranspiration in different stages of the growing season in Fenghuoshan area was （3.03±0.10） mm> （2.49±0.12） mm> and （2.23±0.18） mm， respectively. The calculated crop coefficients and evapotranspiration at different growth stages provide basic data for evapotranspiration observation and simulation in similar areas of the Qinghai-Tibet Plateau.