The invention discloses a pesticide spraying device for a plant protector, which can be conveniently folded. The pesticide spraying device mainly comprises a main arm, two side arms, a main and side arm fixing mechanism, primary and secondary pesticide spraying mechanisms and a side arm resetting mechanism, wherein the main arm is hinged to the side arms; the main and side arm fixing mechanism is arranged between the main arm and the side arms to relatively fix the main arm and the side arms; base plates are arranged on the main arm, and the side arm resetting mechanism is arranged on the base plates; when the side arms are positioned over the base plates, the side arms and the main arm form a U shape, and the side arms are kept in a folded state by the side arm resetting mechanism; the primary pesticide spraying mechanism is arranged on the rear side of the main arm; upper and lower locking plates are arranged on the rear side of the main arm; locking mechanisms are arranged on the locking plates; the primary pesticide spraying mechanism is fixed in a working state and a stored state through the two locking mechanisms; a secondary pesticide spraying pipe is arranged below the side arms, secondary nozzles are arranged at the bottom of the secondary pesticide spraying pipe, and the secondary pesticide spraying pipe and the secondary nozzles form the secondary pesticide spraying mechanism. According to the pesticide spraying device, a pesticide can be effectively sprayed, and the pesticide spraying device can be effectively folded.