The invention provides a preparing method for phenolic resin adhesive for wood. The preparing method includes the following steps that 1, boron carbide powder is added into absolute ethyl alcohol after being dried and stirred to obtain mixed liquid, the mixed liquid is added into an ethyl alcohol solution of KH570, the mixed solution is stirred for reacting after the ph value is adjusted and then stands at the room temperature, and drying is carried out after suction filtration to obtain modified boron carbide for use; 2, by weight, 100 parts of phenol and 70-80 parts of a formaldehyde solution are added into a stirring kettle and uniformly stirred, then 10-15 parts of composite catalysts are added, after heating, a reaction is carried out at the constant temperature under stirring, 2-7 parts of an acid catalyst is added into the stirring kettle, a reaction continues to be carried out at the constant temperature under stirring, 9-10 parts of polyarylester and 5-6 parts of the modified boron carbide are added into the stirring kettle, and a reaction continues to be carried out at the constant temperature under stirring; 3, after the reaction is stopped, the product stands, is placed in deionized water to be washed, and is dehydrated through reduced pressure distillation, dehydration is stopped when the temperature rises to 105 DEG C, and the phenolic resin adhesive for wood is obtained after the product is naturally cooled to the room temperature. The adhesive prepared through the method is good in abrasive resistance, heat resistance and flame retardancy.