The invention provides an epoxy-maleic anhydride type low-viscosity asphalt pavement microcrack quick repairing agent and a preparation method. The method comprises the following steps: adding maleic anhydride and dicumyl peroxide into asphalt and reacting for 3-5 hours at 120-160 DEG C, thereby acquiring maleic asphalt; dissolving the modified asphalt in methyl methacrylate, butyl methacrylate and methacrylic acid and adding benzoyl peroxide, thereby acquiring a component A; adding methyl methacrylate and butyl methacrylate into epoxy resin, stirring till fully dissolving, and then adding inorganic filler and gamma-aminopropyltriethoxysilane, thereby acquiring a component B; and taking N,N-dimethylaniline as a component C. The properties of the material prepared according to the invention can meet the requirements for mechanical, thermal and enduring properties of asphalt pavement, the material can coordinately work with the original asphalt pavement and can prolong the service life of the asphalt pavement, and meanwhile, the repairing operation construction is simple and convenient, the repairing time is controllable and the influence on the traffic flow is reduced.