Since the development of precision agriculture technology, precision spraying, as one of the key technologies of precision agriculture, has been an important issue studied. In order to further study precision spraying, the partition width variable spraying method based on double way control was proposed, and the pesticide precision spraying test bench was set up to measure and test the effective nozzle under the proportional solenoid valve control. The test found that the error between the effective spray amplitude and theoretical value was less than 20%, when the PWM duty ratio was greater than 60%, which had reference value. During the test, the partition width of the spray prescription map was selected according to the effective spray amplitude, and 0.5m,0.75m and 1m were used as the test parameters. Orthogonal tests with spray height, travel speed, and partition width were designed from the selected parameters, and regression equations were obtained, and the correctness of the model was tested by residual analysis. The spray height was 1.5m, travel speed 0-0.5m/s and partition width 0.7-0.9m. Field experiments showed that spraying with optimized zone width saved 23% of the dosage compared with conventional spraying, while the effective coverage could reach 90.7%.