Objective To study the effect of high voltage electric field(HVEF)on growth of Wistar rat and to discuss its biological mechanism.Methods 36 adult Wistar rats of 8_weeks_old age were randomly divided into three groups: control group A,treated group B and treated group C.Each group has 6 males and 6 females.The two treated groups were exposed to different kinds of HVEF.After 12 weeks'experiment,the growth indexes(such as the curve of weight changes,measurements of body conformation,the coefficients of main visceras)of rat were measured.Results The body mass of rat in treated group B was heavier than that of control group A(P < 0.05).The coefficients of liver,kidney and brain of rat in treated group B were lower than that in control group A(P < 0.05).The coefficient of liver of treated group C was lower than control group A(P < 0.05)Conclusion Steady HVEF may prominently increase Wistar rats' body weight and improve their growth rate.Pulsed HVEF of ultra_low frequency has little effect on rat.