The invention provides a powder quantitative dosing device. The device comprises a casing, a threaded cover, a rotation cover, a spray nozzle, a quantitative dosing disc, a scraping plate, a dosing cabinet, a counter, a blocking barrel, a spring blocking plate, a spring, a dust-proof cap and an air bag. The device is simple in usage step, accurate in powder usage, good in medicine storage safety, wide in applicable people, low in requirements for the usage environment and capable of facilitating patient medicine taking, improving the medical quality and saving medical fee expenditures.