A waste rejecting mechanism for die-cut products is mounted on a die cutting machine. The die cutting machine comprises a paper tape tension adjusting device, a die cutting station, a separating and conveying device, and a stacking conveying belt. The waste rejecting mechanism comprises an information processing unit, a scanner and a rejecting device, wherein the information processing unit is mounted on a frame of the die cutting machine, the scanner is mounted above a paper tape guide roll of the paper tape tension adjusting device, the rejecting device is mounted on the stacking conveying belt, the scanner and the rejecting device are connected with the information processing unit through wires, the rejecting device comprises a fixed frame and a rejecting cylinder, the fixed frame is mounted above the stacking conveying belt, the rejecting cylinder is mounted on the fixed frame at a position beside die-cut products stacked together, and a push plate is mounted on a moving rod of the rejecting cylinder. By means of the waste rejecting mechanism, products are detected mechanically instead of manually, waste products in the products are handled mechanically instead of manually, detection accuracy is improved, and labor input is reduced further.