Abstract: A injection molding die includes a first molding unit, a second molding unit, at least one slide block, and a number of elastic elements disposed between the slide block and the first molding unit. The first molding unit includes a first molding surface and a sidewall surrounded the first molding surface. At least one gap is defined in an edge between the sidewall and the first molding surface. The gas hole is exposed at the gap for providing gas to the gap. The slide block is capable of moving toward or away from the sidewall, and includes a protrusion for engaging in the gap to cover the gas hole. The protrusion includes a protrusion surface coplanar with the first molding surface. The second molding unit includes a second mold surface defining a mold cavity cooperated with the first molding surface, the protrusion surface, and the at least one slide block.