The invention relates to a stone paper film forming technology. A stone paper film forming device consists of an extruder and a film blowing device, wherein the extruder and the film blowing device are horizontally arranged in a straight shape, do not have high requirements on plants, are not limited by fields, are safe, have simple technology and low cost, and are produced in a dry method without pollution; the extruder is provided with a feed press-in heating segment, a foamed assistant infusion interface and cooling temperature control mixing segment, and a heating melt extrusion segment; the film blowing device comprises a compressor, a compressed air charge interface, an air blower, an air-cooled air ring, a V-shaped gradually flattened and planished transition frame, and a traction stretch flattening roll. The extrusion and film blowing technology is characterized in that inorganic stone powder and other materials are modified and mediated into ball-shaped materials, fed, pressed into the extruder and heated, a foaming agent and a nucleating agent are infused according to the need, the materials are gradually heated to be melted so as to extrude an O-shaped tip, the compressed air is charged into a paper film tube for film blowing, and a paper film base material is formed via traction stretch, external air cooling, shaping and rolling; and then a stone paper product is formed via edge cutting, corona, coating, drying and finishing.