A medical pesticide spraying apparatus comprises a bottom plate, a supporting device, a first motor device, a rotary plate, a barrel device, a second motor device, a pumping device, a cylinder device and an air spraying device, the bottom plate is provided with a first supporting block, a first roller and a first groove, the supporting device comprises a first supporting post, a first support, a second support, a first holding ring, a first supporting rod, a first holding wheel, a first fixing ring, a first fixing block, a third support and a first sliding block, the first motor device comprises a first motor, a first transverse rod, a fourth support, a first rotary shaft, a first gear and a first positioning shaft, and the rotary plate is provided with a second supporting block, a second positioning shaft, a fifth support, a first supporting ring, a second gear, a second supporting ring, a second supporting ring, a power supply, a sixth support, a third supporting rod and a first limiting block. The invention reduces labor intensity, improves labor efficiency of workers, provides high spraying quantity and enables spraying for a large-space area.