Concrete cracks increase significantly in the surface porous structure of under high temperatures or fire damage. In this study, we investigate the different grout ingredient proportions including epoxy, harder content and the appropriate amount of diluent agents in grout. We then use direct pressure impregnation to fill the cracks in the fire-damaged concrete. The repair efficacy was used to assess the efficiency of compressive strength and tensile strength for the different degrees of fire-damaged concrete. The results of this research showed the ingredient materials of epoxy grout was the ratio of epoxy resin:diluents agent:hardener = 90:10:50 (weight ratio) under the impregnation pressure of 0.12 MPa for 60 min. The ingredient of epoxy grout obtained a great recovery effect to repair the cracks for concrete damaged by fires of 500°C to 700°C.