In this study, a green catalyst prepared by Co and salicylic acid-treated steel converter slag particles (Co-SAM-SCS) and intruding into an EF system (3D-SCS-EF) to treat organic matter and NH3-N in stabilized actual leachate landfill. The COD degradation depends on hydroxyl radicals (∙OH) by activation of BDD anodic catalysis and Co-SAM-SCS catalytic particles; The removal of NH3-N depends mainly on the indirect oxidation of ClO− produced by the carbon felt as the cathode; The product Fe3+ can be reduced to Fe2+ by the electrode, and it can be reused 5 times with an 82 % removal rate of COD. We obtained the optimum the device (particle size of 200–250 mesh, Co loading of 8:1, the dosage of 13 g/L, the anode of BDD); and the optimum operating conditions (initial chloride concentration = 3.12 g/, the current density of 1.5 A/cm2, aeration flow of 2 mL/min). The removal rates and of COD, NH3-N were 88.63 %, 89.47 % and energy consumption was 87.50 kW·h/kg COD, respectively. The TOC removal rate of the treated effluent reached 73.26 %, the biodegradability (BOD/COD5, B/C) value was increased from 0.25 to 0.33, the organic species were reduced, the removal of hard-to-degrade organic compounds was good, and the biochemical properties of the wastewater were improved.