The work aims to reduce the energy consumption of plasma electrolytic oxidation of Mg-Li alloy under the premise of ensuring the corrosion resistance of the coating. The conventional NaOH-Na2SiO3 electrolysis system and the self-developed NaOH-Na2SiO3-Na2B4O7-Na3C6H5O.2H2O (sodium citrate) low energy-consumption electrolysis system were used, respectively, to conduct plasma electrolysis oxidation of LA91 Mg-Li alloy, and the discharge process was investigated separately. The surface morphology, elemental composition and phase composition of the plasma electrolytic oxide coating were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and GIXRD respectively. The corrosion resistance of the coating was tested by electrochemical polarization curve and salt spray test. The unit energy consumption of Mg-Li alloy was reduced to 12.87 kJ/(dm2.μm) by plasma electrolysis in low energy-consumption system, saving about 50.34%. Characteristic pores of plasma electrolysis oxidation were produced on the surface of the coating in both systems. The pores in the low energy-consumption system was small but the pore diameter was more different with a porosity of 14.21%, while the pores in the conventional system was uniform but with a large number, with a porosity of 13.93%. O, Mg, Na and Si were the main elements on the surface of both coatings. The main physical image of the coating prepared in the low energy-consumption system is the single phase of periclase MgO, while the phase composition of the coating prepared in the conventional system is more complex. Salt spray test and electrochemical results show that the corrosion resistance of Mg-Li alloy can be improved by plasma electrolytic oxidation in both systems. After low energy plasma oxidation treatment, the corrosion current density of magnesium lithium alloy is reduced by about 3 orders of magnitude, the corrosion rate is reduced by about 2 orders of magnitude and the self-corrosion potential positively shifts 0.261 V. The corrosion resistance of Mg-Li alloy is effectively improved and the corrosion resistance is better than that of conventional systems. The results show that the electrolyte plasma electrolytic oxidation with the use of low energy-consumption system can form the plasma electrolysis oxidation coating with a hole feature different from that under the conventional system. The thickness and the porosity of coating under the low energy-consumption system show little difference from that under the conventional one, the use of low energy-consumption system can fabricate plasma electrolysis oxidation coating with a better corrosion resistant performance as well as reduce energy-consumption.