The invention discloses a renewable dechlorinating agent and a method for preparing the same. The renewable dechlorinating agent comprises, by weight, 10-45% of active component, 45-85% of carriers and 5-15% of other additives. The active component is mixed metal oxide of iron, copper and zinc, the carriers are materials with large specific surface areas and pore passages, and the other additivesare calcined products of methyl celluloses which are strength improvers, sodium carboxymethyl celluloses and alkaline silica sol. The renewable dechlorinating agent and the method have the advantagesthat oxidation components of the renewable dechlorinating agent further can be activated after reduction pretreatment is carried out on the renewable dechlorinating agent, accordingly, the reaction activity of the renewable dechlorinating agent can be greatly enhanced, and the chlorine capacity further can be obviously improved and is higher than the chlorine capacity of existing dechlorinating agents by 15-35%.