A novel microwave heating self-healing functional material (MHSFM) that can quickly repair concrete cracks was prepared by using thermally expandable microspheres, paraffin, and graphite. The effect of the thermally expandable microspheres dosage on the volume expansion rate of MHSFM was studied, and the heating rates of MHSFM and mortar with MHSFM under microwave were tested. The effect of MHSFM dosage on the mechanical property, impermeability and self-healing performance of mortar was evaluated. The results show that the volume expansion rate of MHSFM gradually increases, as the dosage of thermally expandable microspheres increases. Under microwave, the heating rate of mortar increases obviously with the increase of MHSFM dosage. MHSFM has a certain effect on the mechanical property and impermeability of mortar, but it significantly enhances the self-healing performance of mortar. The mortar with 12% (mass fraction) MHSFM can quickly heal 0.53 mm crack under microwave.