Plastic bottle cap extrusion molding machine is to add granular plastic into the hopper after heating, screw extrusion and scraping off by automatic feeding system, automatically put into the corresponding mold cavity, and make the bottle cap molding and come out through the reciprocating movement of hydraulic mailbox. The whole process does not need manual operation and has high degree of automation. The most commonly used products are mineral water cap, gas cap and beverage cap.