A composite coating based on phytic acid and permanganate was developed on AZ31 magnesium alloy via two-step chemical conversion process, exhibiting high corrosion resistance and low contact resistance. The morphology, composition, anti-corrosion properties and electrical properties of the composite coating were characterized. The composite coating was mainly composed of magnesium phytate, MnO2 and Mn2O3. The corrosion protective efficiency of the composite coating is 80.25 %, which is higher than that of the phytic acid coating and potassium permanganate coating. Furthermore, the composite coating shows low electrical contact resistance around 0.083 Ω cm2, which is close to the potassium permanganate coating but much higher than the phytic acid coating. The high corrosion resistance and electrical conductivity of the composite coating can be attributed to the growth of conductive manganese oxide at the cracks or pores of the anti-corrosion phytic acid coating.