Evapotranspiration process is the principal componet of hydrological budget on land surface and is the main form of earth system′s water consumption.However, the land surface evapotranspiration on the measurement and estimation problem has never been a very good solution. In this paper, by using the historical observation data from DIXI land surface′s comprehensive observation station in LOPEX experimental area,the annual variation and integral total amount of the land surface evapotranspiration of lysimeter, eddy correlation method, Penman method, and evaporation pan observation of four methods  are compared and analyzed to find  that different  observational methods  in measurement of  evapotranspiration have quite different results. The annual variation and seasonal variation of the ratio of eddy correlation method and lysimeter、the ratio of Penman and pan,as well as the ratio of Penman method and lysimeter method are studied. At the same time, the ralation of the ratio of the different methods and local micrometeorological characteristics are discussed.