The invention discloses a method for reinforcing and deviation correcting of building foundation through combined grouting. According to the method, polyurethane grouting and cement grouting are combined organically, polyurethane grouting drill holes are formed in the area where the maximal sedimentation occurs of the building foundation, the polyurethane reaction raw material slurry is grouted into the drill holes, the chemical reaction expansion is generated, so that the area where the maximal sedimentation occurs of the building foundation can be reinforced and lifted, meanwhile, cement grouting drill holes are formed in the periphery of the polyurethane grouting drill holes in a certain density, the pre-existing pores, pre-existing gaps and gaps generated after the polyurethane grouting foundation is lifted in the reinforced foundation are filled and reinforced through the cement grouting method, and a cement-reinforced body is formed. The method has the advantages the reinforcing and lifting of the building foundation through the polyurethane grouting are quick and precise; the building foundation is evenly and comprehensively reinforced through the cement grouting; the construction process is simple, convenient and fast, and the cost is low.