The invention relates to a method for pre-molding and paving a composite material and belongs to the technical field of paving and molding the composite material. The method is characterized by comprising the following steps: 1, firstly, decoiling a paving strip of the composite material; and peeling off paper and a film on the paving strip; 2, subsequently, operating a cutting track control program; utilizing an ultrasonic vibrating cutter to cut the paving strip into a pre-designed shape; and taking out the scrap which is cut off; and 3, extruding and enlacing the cut paving strip which is stuck with the paper and the film to form a coil, so as to be stored or mounted on the paving head for paving. The method can cut various paving strips with complex shapes and can meet requirements of paving and molding various heterotypic core moulds.