The invention relates to a powder loading machine. The powder loading machine comprises a machine frame, a material barrel arranged on the machine frame, a material scraping frame arranged in the material barrel, a tray arranged below the material barrel, a material box arranged in the tray, a first air cylinder controlling the tray to move front and back, and a second air cylinder controlling the tray to move left and right. The material scraping frame comprises a front oblique plane, a back oblique plane, a left oblique plane and a right oblique plane. When the tray moves front and back and moves left and right, powder piled in the material box is compacted through the oblique planes of the material scraping frame; then when the material box is moved out, materials higher than the opening of the material box are scraped off through a material outlet of the material barrel; since the materials in the material box are compacted, the weight is controlled. The design is simple and reasonable, and the trouble of manual measurement is saved.