Abstract: In order to improve technology of tobacco topping and restrain-germinating, the 3YDX-3 tobacco multifunctional machine was empoldered. It was mainly composed of a blower, a tobacco height identification system, a topping system, a spraying system and a culter disinfecting systerm. The works of topping, spraying and culter disinfecting could be finished at the same time. The multifunctional machine could be used for tobacco of different height and different row spacing because of its adjustable rack and movable bracket. The technology of mechatronics was adopted on tobacco height identification system and spraying system, which made accurate measuring and topping, targeted spraying come true. The experiment showed that the multifunctional machine worked safely and reliably, and had accurate topping and spyaying with the productivity of 0.48 hm2/h. It can meet the application requirements.