Since the ground surface is uneven in the field, the body of the high-clearance sprayer is prone to tilt in the rolling direction during operation and the spray beam tends to incline and even touches the crop or the ground, which is the potential of accident. Considering this problem, an automatic spray beam leveling system for the high-clearance sprayer was developed by using a mechatronicshydraulic integrated control method. An electronically controlled hydraulic leveling mechanism was designed to connect with the spray bar through a hinged point that allowed rotation of the spray bar relative to the vehicle body in the rolling direction. The attitude measurement method was used to detect the roll angle of the beam in real time, and the average value of the roll angle was filtered to accurately sense the posture of the beam. An incremental PID algorithm was used to calculate and output signals to the solenoid valve to control the cylinder so that the spray beam was automatically adjusted in the roll direction. Taking the Huasheng Taishan 3WP-500G sprayer as the platform, the newly developed automatic spray beam leveling system was tested by changing the threshold and the average number of the filter, the system response rate, the control stability and error were analyzed, according to which the combination of parameters was optimized. The step results showed that the maximum value of the leveling error was 1.84°, the root mean square error was no more than 0.689°, and field results showed that the maximum value of the leveling error was 1.53°, the average value was 0.135°, and the root mean square error was no more than 0.5°, the angle of the sprayer beam after leveling was within 1°, and the angle was below 0.5° for more than 70% of the time, which indicated that the automatic spray beam leveling system can meet the requirements of automatic beam leveling control. The research result can improve the operation quality and safety of the sprayer and also can provide a reference for the automatic leveling of the spray beam.