The invention relates to the field of injection molding, in particular to a novel zipper socket conjoint injection mould which comprises an upper mould and a lower mould. A pull rod and a spring pullrod are movably mounted on the lower mould, a first loose core and a second loose core are fixedly mounted on the pull rod and the spring pull rod respectively and vertically staggered in a square cavity, a third loose core is fixedly mounted on the first loose core, and a pull rod control device is arranged on the lower mould. The first loose core and the second loose core are provided with embedding holes for placement of bolts, the first loose core is inserted into or pulled out of the square cavity from an upward side to enable incomplete through of the bottom of the square, bolt bottom positioning can be realized while step positioning is omitted, side wall thinness of the square and the bolts are avoided, and tear strength is improved. In addition, the third loose core is provided with a through groove for placement of a side strip matched with the corresponding bolt, the outer end of the third loose core is provided with a round angle, two sides of the third loose core are in inclination of 1.5 degrees to realize shrinkage compensation, and roughness of the side strip matched with the corresponding bolt is avoided.