Abstract: For significant differences in plant morphology between tobacco rosette and topping stage after transplanting, using the single boom sprayer leads to poor disease and pest control.This paper designs a boom and tunnel two-in-one sprayer, to conduct boom spray to sparse and low tobacco in the rosette and exuberant growth stage, and to conduct tunnel spray to tall and dense tobacco in the topping and pro-harvest stage, and to collect drip liquid for recycling.This sprayer is fixed on a high clearance universal chassis.The frame slip deformation mechanism achieves the transformation of two spraying mode between the boom spray and the tunnel spray.The frame collapsed mechanism achieves the transformation of the machine conditions between working state and transport state.Laboratory experiments showed that: compared with the ordinary boom sprayer, both working at tobacco topping and harvesting stage, setting by traveling at the same speed and spraying same amount, this two-in-one sprayer improves about 50% droplets deposition of per unit front area at the lower plants leaves along the vertical direction, and droplets deposition of per unit back area on the lower and upper leaves increases by 30.56% and 61.54% respectively.The droplets deposition of per unit front area on the outer, middle and inner leaves all increased by more than 42% along the horizontal direction, and the droplets deposition of per unit back area on inner, middle and outer leaves also increases by 46.23%, 61.17% and 24.11% respectively.Field experiments also show that: spray droplets have good adherence to tobacco, and almost no damage to tobacco leaves.In the tobacco entire life cycle within field planting, this sprayer has better deposition effect and machine utilization.