Water budget is an essential parameter for crop water management and optimal allocation of the regional agricultural water resources. Longterm observations of meteorological data were collected from 1955 to 2014 in 27 agricultural meteorological stations in Liaoning Province, and relevant physiological information of maize was also recorded. Through analyzing the spatial and temporal distribution characteristics of evapotranspiration (ET) and water budget of maize, the results were got as follows: ET of maize reached the highest in west of Liaoning Province (greater than 380mm), while the lowest was obtained in south of Liaoning Province (less than 345mm). The trend of water budget was increased from northwest to southeast of Liaoning Province, and water deficit was quite common in western part. There was a decreasing trend of yearly water budget within the whole Liaoning Province, which significantly happened in west and north of Liaoning Province (UF＜U0.05/2=1.96)，and very significantly happened in middle of Liaoning Province （UF =-2.89＜U0.01/2=-2.58），their decrease rate reached 19.465mm/10a. Water budget determined by the typical year method were higher than that determined by the virtual year method in most of the research sites (55.6%~81.5%). Among different hydrological years, the consistence of the results from high to low showed as follows: wet year, dry year, drought year and normal year. Besides, their difference was found to be lower than 30mm in most of the research sites (48%~74%). In order to improve the accuracy of corn water budget in Liaoning Province, a combination model was used. The results showed that with the increase of hydrological frequency (from wet to dry of hydrological year), regions showing water deficit were increased gradually. There was only water deficit in Chaoyang region in wet year, but in drought years it was widely expanded to the whole province except Benxi City and Dandong City in east of Liaoning Province.