The invention discloses an adjustable spraying device for forestry. The adjustable spraying device comprises a bottom plate, a mixing tank, a sprayer, a motor, a crankshaft, a rod journal, a first sleeve, a second sleeve, a first rack, a first gear, a stirring shaft, stirring rods, a water outlet pipe, a booster pump, a second rack, a second gear, a rotary shaft, a first support rod, a first electric push rod, a second support rod and a second electric push rod. The adjustable spraying device has the advantages that the device is provided with the motor, the crankshaft, the first sleeve, the first rack, the first gear, the stirring shaft and the stirring rods which are coordinated to drive the stirring rods to rotate forwardly and reversely, fertilizer, chemicals and water can be sufficiently mixed favorably, the second sleeve, the second rack, the second gear and the rotary shaft are coordinated to drive the sprayer to rotate forwardly and reversely in a certain range to increase thespraying range and work efficiency, the height and inclination angle of the sprayer can be adjusted by the first electric push rod and the second electric push rod, targeted spraying can be performedon the different parts of different plants, and the device is high in applicability.