The invention relates to an accelerator for rapidly heating an asphalt pavement through microwaves and a preparation method and application method of the accelerator. The accelerator is prepared by mixing deionized water, petroleum ether, a regenerating component, a dispersing agent, a surfactant, a microwave absorbent, inorganic filler silica, a microwave shielding agent and a stabilizer. The microwave shielding agent and microwave absorbent are mixed in emulsion which has a function for regenerating aged asphalt, and by utilizing the characteristics of microwave interception of the microwaveshielding agent, efficient microwave utilization of the microwave absorbent and aged asphalt regeneration of the regenerating emulsion, improvement of the utilization rate and conversion rate of themicrowaves and rapid heating of the asphalt pavement are achieved, so that the purpose of rapid in-situ regeneration of the asphalt pavement is achieved; furthermore, the utilization rate and conversion rate of the microwaves can be increased by one time or above, the time of asphalt pavement heating through the microwaves can be shortened greatly, and energy and resources can be saved.