The invention discloses a method for processing vehicle bump at a bridge head of an existing highway, and the method comprises the following steps: mixing lightweight materials at a construction site; drilling holes from embankment slopes on both sides of the highway, and automatically discharging soil outward from a threaded opening while rotatably drilling holes; after a designed depth reaches, rotatably and slowly pulling out a drill rod, and starting a booster pump so as to pump the lightweight materials into the obtained drill holes by virtue of a central tube of the drill rod; and jetting the lightweight materials from the central hole of the drill rod so as to gradually fill the hole from bottom to top, thereby replacing the filled soil of an embankment. The drill holes are arranged squarely or quincuncially on the side slope of the embankment, a certain included angle is formed between each drill hole and a horizontal plane, and the elevation of the opening of each hole is positioned below a pavement structure layer and above the underside of the filled soil of the embankment. By using the method disclosed by the invention, the weight of the embankment is greatly reduced, thereby reducing the settlement after construction caused by embankment loads and then effectively solving the problem of vehicle bump at bridge heads. During the construction period, the highway is not required to be closed, therefore, the normal traffic of the highway is not affected. The method disclosed by the invention is simple in construction process, convenient to operate, simple in equipment, economical, and high in efficiency.