The invention discloses a preparation method for an anti-radiation gossypium arboreum fiber. The method comprises the following steps: soaking the gossypium arboreum fiber into sulfolane, performing suction filtration, soaking in a NaOH solution, washing with water till being neutral, wetting with ethyl alcohol, performing suction filtration, soaking into sulfolane again, and performing suction filtration, thereby obtaining an active gossypium arboreum fiber; adding NaOH for regulating the pH of the reaction solution, adding epoxy chloropropane for performing epoxy group reaction, washing and drying, thereby obtaining epoxy gossypium arboreum fiber; adding isopropyl alcohol and diluted alkali for regulating the pH of the reaction solution, controlling the temperature under gas shield, adding 10% HBP-NH2 for performing amination reaction, washing and drying, thereby obtaining amino gossypium arboreum fiber; and adding dissolved 5-amino-2,4,6-triiodoisophthalic chloride and reacting with triethylamine under the conditions of argon shield and ice-water bath, washing and drying the product, thereby obtaining the anti-radiation gossypium arboreum fiber. The preparation method for the anti-radiation gossypium arboreum fiber, provided by the invention, is simple, is low in cost and has the advantages of radiation resistance, nontoxic effect, softness, light weight, skin-friendly effect, wearable property and washable effect.