The invention discloses an injection molding machine with a thick film pressure release shaft protection structure. The injection molding machine structurally comprises a feeding box, a heating screwpipe, an extruding head, a mold, a driving arm, a discharging hopper and a machine body, the feeding box is vertically fixed to a feeding hole of the heating screw pipe through a bolt, the heating screw pipe is welded and fixed on the left side of the extruding head and the edge of the heating screw pipe is subjected to seamless treatment, the mold is horizontally fixed on the left side of the heating screw pipe to form a straight line, the mold is meshed with the threads of the transverse rod on the right side of the driving arm through the inner threads on the left side in conclusion. According to the injection molding machine, the air flow is controlled through a flow passage inside the temperature-sensing variable-cavity heat conduction, a pressure relief shaft is controlled to discharge air at the later stage of injection, meanwhile, the interior slurry is inhibited so that the situation that the internal density cannot reach the production requirement due to excessive pressure relief is avoided., and burrs generated by the pressure relief opening can be automatically scraped after being cooled.