In order to impart electrical conductivity to the magnesium alloy micro-arc oxidation (MAO) coating, the electroless copper plating was performed. Effects of plating temperature and complexing agent concentration on the properties of the electroless copper plating layers were studied by measuring their microstructure, corrosion resistance and electrical conductivity. It was found that the optimized plating temperature was 60 °C, and the most suitable value of the complexing agent concentration was 30 g/L. Under this condition, a complete and dense plating layer could be obtained. The formation mechanism of the plating layer on magnesium alloy MAO coating was analyzed. A three-stage model of the plating process was proposed. The square resistance of the plated specimen was finally reduced to 0.03 W/ after the third stage. Through electroless copper plating, the MAO coated sample obtained excellent electrical conductivity without significantly reducing its corrosion resistance.