The invention relates to a method for producing a vehicle tire flap by using waste tire rubber injection and a product thereof. The method comprises the following steps: (1) desulfurization regeneration: a waste tire is separated to obtain steel wires, fibers and thick rubber particles after the cleaning, the steel wire drawing, the crushing, the magnetic separation and the screening; and after the thick rubber particles are grinded to powder, the desulfurization regeneration is performed; (2) mixing pelletizing: the mixing seal milling and the mixing open milling are performed for regenerated rubbers and other raw materials in sequence; pieces are discharged after multiple times of thin passing; and finally, the rubber materials are extruded for pelletizing; (3) injection molding: the rubber particles are injected to form a flap; and (4) water cooling shaping: the high-temperature flap coats a corresponding rim model; the lower part of the rim model is dipped in cooling water; and the rim model rotates to uniformly cool the high-temperature flap to the room temperature by water. The method not only can reduce the production cost and the environmental protection, but also can directly inject to mold the flap to improve the production efficiency, facilitates to separately perform all the steps in different places, and reduces the equipment and place investment.