It is difficult to monitor and predict the fruiter water deficit quickly and accurately at present. A model for predicting soil moisture in root region of jujube was established with canopy-air temperature differential as the indictor, which was based on the theoretical model of canopy-air temperature differential. Regression analysis was used to analyze the relationship between relative water content of soil, canopy-air temperature differential and meteorological factors, which made the model become more specific. Furthermore, the reliability of the model was analyzed. The results showed that the relationship between canopy-air temperature differential and the soil moisture in the root zone of jujube was the most significant (P<0.01) at 14:00 on sunny days. The soil moisture condition of jujube root area could be obtained more accurately by using the complete predicting model (average relative error MRE≤6%). The generalized predicting model could be used to predict soil moisture in jujube root region within a certain error range (average relative error MRE≤10%). The canopy-air temperature differential was higher than the threshold value in jujube tree growth period, indicating that the jujube needed irrigation, otherwise irrigation is not needed. The model for predicting soil moisture in root region of jujube based on canopy-air temperature differential can diagnose jujube water deficit effectively and provide guidance for scientific irrigation of jujube.