The invention discloses an alloy steel surface coating cladding method. A surface coating comprises, by mass, 30 to 35% of ferrotitanium, 14 to 16% of ferrochromium, 14 to 16% of ferromolybdenum, 20 to 25% of graphite, and the balance pure iron powder. According to the alloy steel surface coating cladding method, alloy steel surface coating cladding is realized via following steps: alloy powder configuration is carried out, laminar plasma jet coating cladding equipment setting is carried out, coating cladding pretreatment is carried out, coating cladding treatment is carried out, coating cladding aftertreatment is carried out, and a heat source is provided by a laminar plasma generator under certain parameter setting. According to the alloy steel surface coating cladding method, the special heat source is provided by laminar plasma beam, and special setting of technological conditions and parameters are carried out, so that the alloy steel surface coating cladding method is simple, an obtained alloy steel surface cladding coating possesses wear resistance, high compactness, and alloy steel surface modification quality is improved.