The daytime evapotranspiration (E) was measured using the eddy covariance (EC) technique, the mini-lysimeter method, and the Bowen ratio-energy balance (BREB) method, in an alpine meadow ecosystem on the Qinghai-Tibetan plateau during the growing season of 2005 and 2006 (Jul.-Aug.). The energy imbalance with a slope of 0.73 was found in this study. Results showed a significant correlation between the E measured with the three methods, with the correlation coefficient of 0.96 between the EC technique and the mini-lysimeter method, and 0.95 between the EC technique and the BREB method. However, the value of E measured by the BREB was the largest, which was 43% higher than that by the EC; whilst the E measured with the mini-lysimeter had the medium value, which was 19% higher than that by the EC. The results suggest that the E may be underestimated using the EC in this alpine meadow on the Qinghai-Tibet Plateau.