The invention discloses an acid residue resisting agent for oil well acidizing, a preparation method therefor and acid residue resisting acidizing fluid. The acid residue resisting agent for oil well acidizing is prepared from the following ingredients in parts by weight: 30-50 parts of ethylene glycol monobutyl ether, 15-30 parts of iron ion stabilizer, 1-3 parts of ammonium chloride and 70-90 parts of water. The acid residue resisting agent for oil well acidizing, disclosed by the invention, is extremely easy to disperse in acid liquor, is good in compatibility with other acidizing additives and is mainly applied to the acidizing of high-coagulability oil reservoir flooding wells; during acidizing, the acid residue resisting agent is distributed on an interface of acid and crude oil, so that the contact between the acid and the crude oil is reduced, and the acid liquor is prevented from forming acid residues with colloidal matters, asphaltenes and the like in the crude oil; and the acid residue resisting agent entering the crude oil is combined with sulfur-bearing and nitrogenous parts in the colloidal matters and the asphaltenes according to polarity-close rules, the reaction between the colloidal matters/asphaltenes and an acid and the complexation of the colloidal matters/asphaltenes with iron ions are reduced, and the acid residue resisting agent plays a good role in resisting acid residues when the acid residue resisting agent is applied to the acidizing of the high-coagulability oil reservoir flooding wells.