The invention relates to a composite modified anti-rut agent and belongs to the field of road engineering materials. The composite modified anti-rut agent comprises the following components in percentage by mass: 40-70% of a regenerative thermoplastic polymer, 10-30% of recycled rubber powder, 5-15% of an inorganic filler, 1-5% of a coupling agent, 2-8% of a co-solvent and 1-5% of lignin fibers. According to physical and chemical properties of solid wastes, a certain amount of additives are added for organic combination, and the asphalt mixture anti-rut agent is prepared, so that the high andlow temperature performances of the asphalt mixture are obviously improved. Meanwhile, according to productive raw materials, multiple solid wastes can be effectively utilized, obvious environmental benefits are achieved, and the overall cost of the anti-rut agent can be reduced.