Abstract: At present, there are some problems in the operation process of tobacco plant protection machine, such as low intelligence, large atomization droplets and unable to cover the whole leaf surface. Based on ultrasonic technology, an intelligent tobacco plant protection machine is designed and developed in this paper, which is based on electric chassis, and integrates the main components of ultrasonic atomization, wind spray and intelligent control system. The performance test is carried out by combining theoretical analysis with indoor experiment. The test results show that when the pressure is 0.3 MPa, 0.5 MPa and 1.0 MPa, the spray amount of the plant protection machine is less different from the theoretical value, and the uniformity is more than 95%; By adjusting the wind speed of the fan, the spraying range can also be adjusted between 0～6.56m. the spraying volume, uniformity and spraying range of the plant protection machine can meet the working requirements. It provides a theoretical basis and reference for the development of tobacco plant protection equipment.