The experimental area located in Mizhi experimental station in loess plateau of China. According to the meteorological data observed by automatic weather station of Mizhi experimental station and using FAO Penman—Montieth equation, the crop reference evapotranspiration was calculated consequently in jujube’s growth period. Additionally, combined with crop evapotranspiration of jujubes under sufficient irrigation, the crop coefficient of drip-irrigation jujubes was studied. The water requirements and crop coefficient was determined in each growing period of jujube. Water requirements (crop evapotranspiration) in sprout-leaf development period, flowering and fruit-setting period, fruit development period and fruit development period was 68.1mm, 117.4mm, 224.4mm and 66.2mm, respectively. Crop coefficient in each growth period was as follows: 0.496 in sprout-leaf development period, 0.681 in flowering and fruit-setting period, 1.262 in fruit development period，and 0.944 in fruit mature period. A function relationship was established between crop coefficient and leaf area index, and the results demonstrated that there was a quadratic curve relationship between crop coefficient and leaf area index.