The glass fiber reinforced polymer (GFRP) is widely used in aviation, marine and wind power generation due to its excellent advantages. The extensive utilization of GFRP has resulted in the production of a large amount of waste, which has caused great harm to the environment, and has drawn much attention to the recycling and disposal of waste GFRP. In this paper, waste epoxy-based GFRP and polyurethane-based GFRP powder (diameter < 0.075 mm) were used as bitumen reinforcement materials to study the enhancement effect on the properties of bitumen, and the influence of silane coupling agent on the reinforcement effect was compared. The results show that the two kinds of GFRP powders have no obvious strengthening effect on bitumen, but after surface treatment of GFRP powder with silane coupling agent, it can significantly improve the interaction between GFRP and bitumen to improve the rheological properties and surface free energy of bitumen and reduce the glass transition temperature, in which the improvement effect of silane coupling agent on epoxy-based GFRP is better than that of polyurethane-based GFRP. The results provide a new idea for the recycling of fiber reinforced polymer (FRP).