In order to solve the problem of synthetic void pre-judgment and anti-leakage spray, a new canopy partied volume method of fruit tree was developed based on void pre-judgment. The measurement sensors required were NU40F15TR-2M non-contact ultrasonic ranging sensor and SICK-DT35 non-contact laser ranging sensor, which were fixed on caterpillar self-propelled orchard sprayer. When information of fruits was collected, the vehicle’s traveling speed was 1.0m/s, and the sensor was 1.4m away from the tree trunk. Firstly, NU40F15TR-2M non-contact ultrasonic ranging sensor and SICK-DT35 non-contact laser ranging sensor were used to obtain orchard information point cloud pictures, ahead of nozzle 46cm distance, which were distances between ranging sensor and fruits canopy. Continuous canopy width was calculated based on point cloud picture, and canopy width calculation formula was designed. At the same time, fruits void was reasoned by the formulas, and the abnormal data point was chosen with a negative canopy width value and replaced with data points of zero. Secondly, length of discrete canopy volume model was determined by E6B2-CWZ10C speed, because speed of caterpillar self-propelled orchard sprayer was nonuniform motion in actual travelling. Thus caterpillar self-propelled orchard sprayer travelling distance of a certain period time was calculated by uniform speed of caterpillar self-propelled orchard sprayer and variable rate spraying decision time. And variable spraying decision time was designed by a required time formula, which was satisfied with responsing time, effective spray time of the actuator and the real-time requirement of variable spray. Pulse number of E6B2-CWZ10C speed encoder was calculated based on the principle of itself and caterpillar self-propelled orchard sprayer driving distance of a certain period time. Thus discrete canopy length was obtained by E6B2-CWZ10C speed encoder and variable rate spraying decision time. Finally, fruits void and fruits canopy were judged by a model, which was used to distinguish fruits void, fruits canopy and the mixture of fruits void and fruits canopy. There were fruits void, when the average width was less than one tenth of the maximum width in the distance of discrete canopy length. Therefore, the discrete canopy width value was got and fruit tree canopy volume model was partied. This anti-leakage spray decision was made by designing logic operation. The testing results showed that the fusing sensor array and the blowout prevention strategy were the best. But there was the problem of overspray. By improving the fusion sensor array and testing, compared with the conventional fusion sensor array, the number of droplets in the upper, middle and lower canopy of the continuous dense orchard was decreased by 6.95%, 3.85%, and increased by 4.40%, respectively;the deposition amount was decreased by 11.11%, 8.33% and 3.57%, respectively. The number of droplets in the upper, middle and lower canopy of the spindle-type sparse orchard was decreased by 27.08%, 30.37% and 18.55%, respectively;the sedimentation was decreased by 64.71%, 60.87% and 40.38%, respectively. The number of droplets in the upper, middle and lower canopy of the single plant type sparse orchard was decreased by 18.44%, 26.26% and 15.54% respectively;the sedimentation was decreased by 40%, 42.43% and 41.46%, respectively.