The invention discloses a processing method for recycling waste packaging paper, and relates to the technical field of waste paper recycling. The processing method comprises the following steps of: 1,conveying waste paper into a cutting machine, and sequentially carrying out twice flattening treatment, cutting treatment and crushing treatment on the waste paper in the cutting machine, 2, pouringa waste paper raw material into a magnetic suction rolling cylinder, rotating the magnetic suction rolling cylinder, supplying power for electromagnet in the magnetic suction rolling cylinder to adsorb metal impurities in the waste paper raw material; and 3, pouring the waste paper raw material into a pulping machine, pouring warm water into the pulping machine, conducting stirring to obtain pulp,pouring a deinking agent, a defoaming agent and a dispersing agent into the pulp, and starting an ultrasonic cleaner in the pulping machine to physically clean the pulp. When paper pulp is stirred, the surfaces of fibers in the paper pulp can be physically cleaned through ultrasonic waves, so that the separation efficiency of the fibers in the paper pulp and ink is improved, ultrasonic cleaning and stirring are mixed and used for 2-3 times, and the deinking quality can be improved.