The invention relates to the technical field of tobacco planting, and discloses a pesticide spraying device for tobacco planting, which comprises a medicine box and a medicine inlet pipe, wherein themedicine inlet pipe is fixedly communicated to the top of the medicine box; the side surface of the medicine box is fixedly connected with a pump body; the bottom of the pump body is fixedly communicated with one end of a medicine extraction pipe; the other end of the medicine extraction pipe is fixedly communicated with the bottom of the side surface of the medicine box; a transverse mixing mechanism is connected to the medicine extraction pipe; one end, positioned in the inner cavity of the medicine box, of the transverse mixing mechanism is connected with a longitudinal mixing mechanism; and the transverse mixing mechanism comprises a rotating rod, driving impellers, driven impellers and a driving umbrella gear. The driving impellers are driven to rotate by the flow of the liquid medicine in the medicine extraction pipe, and thus the rotating rod drives the driven impellers to rotate, so that the liquid medicine in the medicine box can be uniformly mixed conveniently, and a power mechanism is not required to be additionally arranged, so that the mixing uniformity of the liquid medicine is increased, and meanwhile, the power consumption is reduced.