In order to alleviate the soil drying of the jujube forest in semiarid loess area, we took the gradient control on jujube tree specifications by pruning, using the TDP tree rod liquid flow monitoring system to monitor the jujube tree transpiration and CNC100 neutron moisture meter to monitor soil moisture. It was found that the pruning on jujube had a significant influence on the transpiration and water consumption at different time scales through the research for two consecutive years. Pruning can significantly reduce the tree transpiration in flowering period of fruit and fruit enlargement period of jujube, and reduce the consumption of soil moisture. Compared with the control treatments, the tree transpiration with mild, moderate and severe pruning of the whole growth period decreased by 31.7%, 52.0% and 68.6%, respectively. The relationship between tree transpiration and specifications were analyzed by linear and nonlinear analysis method, and then a mathematical model of natural precipitation and trim production target was built. The suitable target yield for the sustainable management of jujube forest in northern Shaanxi was 1.2×104kg/hm2, and the tree index for water-saving trim regulation was the crown and the new length. The new mode was formed that the production of jujube was determined by soil moisture and jujube specifications were determined by production.