The invention discloses multielement catalysis iron-carbon micro-electrolysis filler and a preparation method thereof. The multielement catalysis iron-carbon micro-electrolysis filler mainly comprises 55-75 parts of iron powder, 10-30 parts of active carbon powder, 5-20 parts of nonferrous metal powder catalyst A, 5-10 parts of nonferrous metal powder catalyst B and 5-10 parts of inorganic catalyst C. The preparation method comprises the steps of weighing, extruding, primary moulding and high-temperature sintering. The invention has the advantages that the multielement catalysis iron-carbon micro-electrolysis filler disclosed by the invention overcomes the defects that the traditional scrap iron is hardened easily and generated sludge is tripled or quadrupled after reaction because reaction speed cannot be controlled when micro cell reactions are excessive, iron-carbon micro cell potential difference is enlarged, reaction speed is higher, reaction ratio can be controlled, contact ratio of pollutant to a micro cell is tripled, sewage oxidation treatment efficiency is doubled or tripled, no hardening is caused as iron atoms are not in direct contact, and the filler does not need to be replaced or regenerated.