The invention discloses a patching material for processing building cracks, which is prepared from powders of group A, liquid materials of group B through mixing, wherein the weight proportion of the powders of the group A to the liquid materials of the group B is between 0.8 and 2 to 1. The content range of each composition of the powders of the group A is as follows: 30 to 80 percent of 425 Portland cement, 10 to 50 percent of quartz powders, 5 to 30 percent of nano-size calcium carbonate, 1 to 5 percent of polypropylene short fiber, 1 to 10 percent of wood fiber, 1 to 10 percent of methyl cellulose, and 1 to 10 percent of calcium formate; and the content range of each composition of the liquid materials of the group B is as follows: 10 to 80 percent of pure acrylic resin copolymer emulsion, 0.1 to 1 percent of defoamer, 1 to 11 percent of bactericidal preservative, 1 to 12 percent of alkaline swelling thickener, 0.5 to 12 percent of pH modifier, 5 to 20 percent of talc powders, and 10 to 40 percent of water. The construction process of the patching material is performed according to the following steps: base course processing, patching material scraping, and surface layer brushing. A product of the patching material has the advantages of strong cohesive force, high mechanical strength, impact resistance, shock resistance, insolation resistance, water immersion resistance, chemical corrosion resistance, no pollution, excellent physical and chemical properties of the product, strong stress resistance, and certain waterproof effect.