A mold includes a female mold defining a receiving space and a male mold including a body and a core protruding from the body. The male mold and the female mold cooperatively define a molding cavity for forming a molding product. The core includes a distal end portion inserted into the receiving space. The distal end portion is configured for forming a through hole of the molding product. The female mold includes two protruding ribs arranged at a parting line between the female mold and the core. The protruding ribs of the female mold is located on opposite sides of the distal end portion, and extend around the distal end portion. The core includes two protruding ribs formed on the distal end portion at the parting line between the female mold and the core. The protruding ribs of the core extend around the distal end portion.