Abstract:This test selected Fuji Apple in northwest arid area as research object.By using Thermal Dissipation Probe to successively measure the stem sap flow and automatic weather station to synchronously record the change of circumstance factors,we investigated the effects of circumstance factors on stem sap flow velocity (SFV).The main results showed that:Stem sap flow velocity of Fuji Apple in a series of days took on irregular sine curve with different peak values which decreased during the night and increased during the daytime;the sap flow velocity took on obvious single peak curve in clear days while in cloudy days it presented double peak curve or multi peak curve.Whether it was clear days or cloudy days,apple still had weak movement in the night,this phenomenon may have relationship with the unique geographical position and climate condition of Aksu;during the main growth period,sap flow velocity (Fs) had multiple correlation with atmospheric temperature (Ta),solar radiation (Rn) and relative humidity (RH),among which atmospheric temperature was the main influencing factor;in the whole growing season,the total water consumption of Fuji Apple was 4 059.64 L,of which water consumption in July was 765.34 L which was the highest,taking 18.85 percent of total water consumption.Research indicated that thermal dissipation probe can accurately measure the sap flow velocity and water consumption of Fuji Apple,furthermore,the main environment factors affect sap flow velocity are in the sequence of atmospheric temperature (Ta),solar radiation (Rn),relative humidity (RH).