The invention discloses a retrobulbar drug injection device. The device comprises a syringe and a sheath, the syringe comprises a syringe cylinder, a piston push rod, a piston, a first protrusion portion, a first needle, and a first support plate, the sheath includes a sheath cylinder, a second protrusion portion, a second needle, and a second support plate, an inner wall at a far side of the sheath cylinder is provided with internal threads, and an outer wall at a far side of the syringe cylinder is provided with external threads; the end at a far side of the first needle is blunt, and the end at a far side of the second needle is pointed; the portion at the far end of the first needle is provided with one or more drug injection openings; and the bottom surface of the sheath cylinder is provided with one or more air holes. By using the retrobulbar drug injection device, the second needle and the first needle respectively perform the puncture function and the stripping function, and the drug injection openings of the first needle can be employed for drug injection so that the depth of the drug injection position, the drug injection amount, and the drug injection speed can be actively controlled.