The invention belongs to the technical field of soap making, and particularly relates to efficient decontamination soap and a preparation method thereof. The soap is prepared from the following raw materials: peppermint essential oil, potassium hydroxide, a maleic anhydride acrylic polymer, higher sodium aliphatate, lignosulfonate and an additive; the additive is prepared by mixing shell powder, natural aloe and sodium bicarbonate; the decontamination capability of the soap can be improved; meanwhile, sodium bicarbonate can reduce the phenomenon that when the soap is used for cleaning the sweater, the soap belongs to an alkaline substance, so that the sweater cleaned by the soap is hardened; the natural aloe can play a role in moisturizing hands of users; the method is suitable for preparing the decontamination soap. The decontamination soap is prepared by the method, so that emulsion 3 can be uniformly mixed in emulsion 1 and emulsion 2, and meanwhile, the emulsion 1 and the emulsion2 are fully contacted and mixed, so that the decontamination, softening, disinfection and sterilization capabilities of the soap are improved.