The invention discloses a spray control method based on volume feature pre-judging. The method comprises the following steps: the distance detection of the plant canopy on one side or both sides of the sprayer is carried out by using some distance detection points based on the center line of the sprayer body when the spray zone begins; the canopy width corresponding to the detection point is calculated; the maximum canopy width of a canopy partition is used as the width of the discrete spray volume of the canopy partition; the discrete canopy volume of each canopy partition is calculated; theamount of spray and air volume required for the next spray partition is calculated. The invention also discloses a spray control system based on volume feature pre-judging. The method can adjust the spray amount in time and accurately by detecting the spray object and pre-judging the volume in advance and add the precise bypass air regulation fuction which can increase the penetration and deposition amount of the liquid and reduce the spray waste.