The paper bag bottoming machine performs the bottom processing of the paper bag on the already-formed paper bag, the pull-out roller, the bag surface pressing wheel and the mechanical large roller synchronous operation, so that the bottom of the paper bag is perfectly formed. Instead of manual operation, increase efficiency and increase production. It can realize the automatic continuous work of the bottom of the square bottom paper bag, and has the advantages of compact structure, high production efficiency, stable performance and good quality of the hook bottom.