In this paper, high voltage electrostatic field (HVEF) was applied to agricultural production. The experimental equipment of HVEF was designed. To explore the effect of HVEF on physiological characteristics and yield of hydroponic tomato, illustrate the influence mechanism of HVEF on the tomato seedlings, tomato seedlings were cultivated in greenhouse. The seedlings with two true leaves and the same height were transplanted to experimental lab and gone on the treatment of HVEF. The seedlings were cultivated in nutrient solution mode. Three different high voltage electrostatic fields of 2.00, 2.25, 2.50kV/cm were adjusted and the seedlings between the two parallel-electrode plates were treated under this condition for 8 h. After finishing the treatments of HVEF, some of the seedlings were continued to be cultured by using of inorganic matrix and nutrient solution culture in greenhouse. Then, the stem diameter, fresh weight, chlorophyll content and root morphological characteristics of tomato seedlings, as well as ultimate yield of tomato were studied. In addition, root activities and membrane permeability of other seedlings, and the changes of ion concentration of uptake solution as soon as HVEF treatment was finished, were analyzed. The results show that the high voltage electrostatic field, compared with the control (without electric field), changes the growth characteristics of tomato, and the electric field intensity of 2.25kV/cm increases stem diameter, fresh weight and chlorophyll content, and promotes the effect of the optimal root morphology. As a result, the yield is increased by 23% in contrast with the control.