The invention discloses a high efficiency hardening resistant micro-electrolysis material. The porosity is 0.5 to 0.8 and the specific surface area is 0.4 to 1.0m2/g. The preparation method is that at first ferrous powder, active carbon powder, sodium bentonite and NH 4Cl are mixed fully, water is added and stirred evenly, in the second place, small balls the diameter of which is 2 to 5mm are made through a ball forming mill and then dried and finally the dried spherical material is roasted and cooled to room temperature naturally. Compared with the traditional micro-electrolysis material, the invention has the advantages that NH3 generated by NH4Cl at high temperature is used to create pores, the porosity and the specific surface area of material are increased, the elimination effect of the micro-electrolysis material on pollutant in waste water is improved, meanwhile because the material is spherical regular material, the invention has good mechanical strength, the compaction of thematerial in the use process is avoided, the material does not tend to be hardened and passivated, the service life is long and consequently the long-term stable running of the micro-electrolysis technology is ensured.