Method for preparing material containing amorphous iron oxide hydroxide, the method including: mixing an aqueous ferrous salt solution and hydroxide solution or solid hydroxides at the temperature of below 70°C, filtering the reaction solution, washing the filter cake, preparing suspension solution of the filter cake, blowing an oxygen-containing gas into the suspension solution to oxidize the ferrous iron, and then filtering and drying. The material after being used as desulfurization agent can be repeatedly regenerated through oxidation in an oxygen-containing gas. A desulfurization agent, and methods for preparation and repeated regeneration thereof. The desulfurization agent contains the material and organic binders, and may also include a small amount of additives. The organic binders are selected from sodium carboxymethyl cellulose, sesbania powder, and cellulose powder, and the additives are selected from sawdust, rice husk power, and bran.