Abstract: In order to solve the low efficiency of softening old asphalt pavements in hot in-place recycling, the influence factors including the ratio of ingredients for recycling and water, dosage of microwave sensitive material of microwave sensitive asphalt rejuvenate agent permeate through aging asphalt was studied by penetration test, microwave sensitive asphalt rejuvenate agent was developed at last. Through self-designed laboratory test, the result of softening asphalt mixture was validated, and the mechanism of microwave sensitive asphalt rejuvenate agent softening asphalt mixture was analyzed. The results indicate that the microwave sensitive asphalt rejuvenate agent can soften asphalt mixture rapidly under microwave irradiation at a low temperature.