The invention discloses a stamping automatic puller with a one-time molding function. The automatic puller comprises a limiting nose bridge and an elastic piece, wherein the limiting nose bridge and the elastic piece are integrally molded above a puller body. A gap is formed between the elastic piece and the limiting nose bridge, the elastic piece and the limiting nose bridge are molded on an upper boat deck of the puller body side by side, the limiting nose bridge is higher than the elastic piece, and then a pulling piece lifts the elastic piece and limits the lifting height of the elastic piece. One end of the limiting nose bridge and one end of the elastic piece are bent upwards from the end of an engaging opening of the upper boat deck to form fixed ends, and the other end of the limiting nose bridge and the other end of the elastic piece stretch towards the end of a guide-in port of the upper boat deck and then are bent downwards to form free ends. The automatic puller has a simple and smooth integrated appearance, and stamping forming is convenient; when a self-locking function is used, elasticity is enough, resetting is free, no chain blocking is easily caused, and the stamping automatic puller is more stable in the pull-closing use process.