The hard bottom layer of the paddy field is not flat, so the rotary tiller will tilt and vibrate when it is working in the field, which will seriously affect the quality and efficiency of the rotary tillage operation and damage the paddy field leveling. In order to solve these problems, a GNSScontrolled intelligent paddy field rotaryleveling machine was developed. The two GNSS satellite antennas were symmetrically fixed at the two ends of the rotaryleveling machine hood, which was used to receive elevation data of the main antenna and pitch angle data between the two antennas. The received elevation positioning data was the elevation of the rotaryleveling machine, and the pitch angle data was the inclination of the rotaryleveling machine. The fuzzyPID control algorithm was used to output driving voltage signal to the electrohydraulic proportional reversing valve, thereby controlling the expansion and contraction of the cylinder, so that the rotaryleveling machine rotated around the intermediate rotating shaft or moved up and down along the chute to realize the horizontal and height adjustment of the implement. In order to solve the problem of continuous heating of the hydraulic pump, a hydraulic system was designed. In this hydraulic system, the accumulator and the hydraulic pump worked together to reduce the burden on the hydraulic pump. A datum calculation method was proposed, which automatically calculated the datum plane by the least squares method to get the control reference plane conveniently and quickly. In order to verify the working performance of the intelligent paddy field rotaryleveling machine, the paddy field leveling test was carried out under different crop types such as rice, wheat and different soil types such as sandy soil, clay soil and loam. The test results showed that under different test conditions, the flatness of the paddy field was greatly improved, and the average can reach about 3cm. The system had good stability and adaptability. After leveling, the paddy field can meet the agronomic requirements of rice planting.