Abstract: According to the field experiments from 2006 to 2007,the reference crop evapotranspiration was calculated by using Penman-Monteith equation on main crops in the Northern Shandong Province.The actual crop evapotranspiration was achieved by water balance equation and adjustment coefficient of soil water.The evapotranspiration in the whole growing period of winter wheat,summer corn,spring cotton,apple trees and Chinese chive was 491.2 mm,371.0 mm,425.8 mm,666.8 mm and 891.8 mm respectively,while the crop coefficient in the whole growing period was 1.32,1.34,0.85,0.99 and 1.33 for winter wheat,summer corn,spring cotton,apple trees and Chinese chive respectively.

Key words: Crop evapotranspiration, Crop evapotranspiration, Crop coefficient, Winter wheat, Summer corn, Spring cotton, Apple tree, Chinese chive