The invention discloses a high-toughness polyacetal resin composition. The high-toughness polyacetal resin composition comprises polyacetal resin and a crystallization inhibitor which is added into the polyacetal resin, wherein the crystallization inhibitor is a polyformaldehyde resin polymer; in the polyformaldehyde resin polymer, each 100 mol of formaldehyde repetitive units comprise 3 to 6 mol of oxyalkylene structural units. According to the high-toughness polyacetal resin composition, part of crystallization properties of polyformaldehyde can be inhibited by adding the crystallization inhibitor, so that the notch impact strength and the breaking elongation of the resin can be greatly improved; the toughness can be improved; the design at a molecular level can be reached by simple blending and modifying, so that the cost for development, production, formula, debugging and the like is reduced.