Abstract: Reference crop evapotranspiration is an important part of the ecological system of water cycle and water balance, has important significance on the evolution of the fragile ecological environment development in Aletai Area. In order to propose a suitable method of computing ET0 in North Xinjiang, this paper compared the differences and relations between the 5 calculation formula, and analyzed the cause of the deviation, at last evaluated the applicability of computational method by using the May 1st - September 30th in 2010 in Fuhai County Weather Station daily meteorological data. The results showed that, FA056 PM method, FAO Penman method and IA method got approximated calculation results which relative error was 9.26% and 13.51%, ET0 calculated by PT method and HS method had overall greater results at most of the time during the whole growth period.