The invention discloses a precise-quantification dry powder medicament dosing system which is composed of a medicament storage box, a vibrator, a stepping drive device, a spiral conveying device, a waterproof rubber plug, an air cylinder, an air blowing pipe, a material sensor and a PLC control module. The vibrator and the material sensor are arranged at the two ends of the medicament storage box correspondingly. An outlet of the medicament storage box is perpendicularly connected with the spiral conveying device. The spiral conveying device penetrates through the outlet of the medicament storage box to be connected with the stepping drive device. The stepping drive device drives the spiral conveying device to convey materials spirally. A conveying outlet of the spiral conveying device is in butt joint with the waterproof rubber plug mounted on the air cylinder. The air blowing pipe is arranged at the upper end of the conveying outlet of the spiral conveying device. A medicament is dosed through the air blowing pipe. By adoption of the system, the dry powder medicament can be dosed in a precise quantification mode, the medicament dosage is adjusted in real time, an alarm is sent out in case of starved feeding, the functions of automatic waterproofing and moisture proofing are achieved after shutdown, and the precise-quantification dry powder medicament dosing system is novel and precise.