The invention discloses an automatic sandblasting machine. The automatic sandblasting machine includes a machine mask, wherein the machine mask is of a cavity structure. The lower portion of the innerside of the machine mask is provided with an abrasive box, a funnel is arranged at the bottom portion of the abrasive box, and a feeding pipe is arranged at the bottom portion of the funnel. One end,near to the funnel, of the feeding pipe is provided with a first adjustment valve, a grinding cavity is formed in the top portion of the abrasive box, and a filter net is arranged between the abrasive box and the grinding cavity. One side of the machine mask is provided with a waste draining pipe, the waste draining pipe corresponds to the filter net, and a protective net is arranged at the lowerportion of the inner side of the grinding cavity. The inner side wall of the grinding cavity is provided with a plurality of material praying guns. The material praying guns are evenly provided withsecond adjustment valves, and one ends, near to the inner wall of the grinding cavity of the material praying guns penetrate through the grinding cavity and are fixedly connected with air inlet pipes.The automatic sandblasting machine has the beneficial effects that the efficiency of spraying and grinding is improved, the consistency is improved, the appearance and subsequent processing are ensured, and the quality of the final product is guaranteed.