The utility model discloses a demoulding structure for adding a pitched roof on a sliding block of an injection mould, which comprises a movable mould plate, a pitched roof seat is arranged at the upper part of the movable mould plate, a pitched roof is arranged on the pitched roof seat, the top of the pitched roof is connected with the pitched roof seat in a left-right sliding manner, the middle part of the pitched roof is connected with a sliding block, the sliding block is connected with an inclined guide post, and the inclined guide post is connected with a sliding block. A mold core is installed on the lower portion of the movable mold plate, a clamping hook extending rightwards is arranged at the bottom of the inclined top, and a hook groove corresponding to the clamping hook is formed in the top of the mold core. The core-pulling mechanism is simple in structure, easy to install and easy to operate, the upper side face of a product is provided with longitudinal inverted buckles and transverse inverted buckles, core-pulling actions in two directions are achieved, the inverted buckles in the longitudinal direction are subjected to core-pulling through the sliding block, the inverted buckles in the transverse direction are subjected to core-pulling through the inclined top, the sliding block is a driving piece and is heavy, the inclined top is a driven piece, and the sliding block and the inclined top are mutually matched. The stability and the reliability of mechanism movement are guaranteed, the manufacturing period and the production cost of a mold are reduced, and later maintenance is easy.