The invention relates to an inclined core-pulling mechanism of a plastic injection mold, aiming to solve a problem to achieve the purpose of smooth mold opening in plastic injection molding of parts of automotive rear back doors and door plates. The inclined core-pulling mechanism comprises a moving mold insert, an inclined slide block, a wedge-shaped pressing block and a slide block limiting block, wherein the moving mold insert is provided with a plastic injection mold cavity and a cavity for accommodating the inclined core-pulling mechanism, the inclined slide block is arranged in the cavity of the moving mold insert, the top end of the inclined slide block is provided with a lateral mold core matched with a plastic injection workpiece, a wedge-shaped surface structure is adopted by the tail part of the inclined slide block, two side faces of the inclined slide block are respectively provided with a stop block, the upper end faces of the stop blocks are respectively provided with a compression spring, and the bottom surfaces of the stop blocks are matched with the slide block limiting block. The inclined core-pulling mechanism has the characteristics of simple structure, reliable performance and high practicality, the product quality and production efficiency of plastic injection parts of automotive rear back doors and door plates can be improved significantly, and good economic benefits can be produced for enterprises.