The invention discloses a quantitive drug doser for veterinary drug detection. The quantitive drug doser for veterinary drug detection comprises a drug storage cylinder, wherein a powder scraping cylinder is connected to the bottom part of the drug storage cylinder through a connecting shaft; a drug outlet hole is formed in the side wall of the drug storage cylinder; a notch is formed in the sidewall of the powder scraping cylinder; a powder scraping plate is arranged on the outer side of the notch; a bracket is fixed to the outer side of the drug storage cylinder; a clamping plate is hingedonto the bracket through a torsional spring; a tray is connected to the bottom part of the bracket through a first spring body; the bottom part of the first spring body is fixed onto a first adjustingbolt; the first adjusting bolt is in threaded connection with the bottom part of the bracket; a guide wheel is arranged on the inner side of the clamping plate; a metering cylinder is movably arranged in the bracket; the clamping plate is used for clamping and fixing the metering cylinder; the guide wheel contacts the outer wall of the metering cylinder; a drug inlet hole is formed in the side wall of the metering cylinder and corresponds to the drug outlet hole; and a seal ring is arranged on the outer side of the drug inlet hole and contacts the side wall of the drug storage cylinder in a sealing way. The quantitive drug doser for veterinary drug detection provided by the invention can overcome the defects of the prior art, and realizes one-time fast and quantitive dosing.