The efficient liquefaction of cellulose is a critical technological pathway for the energy utilization of biomass. This study constructed a plasma electrolytic liquefaction experimental system based on the principle of liquid phase surface arc discharge, systematically investigating the effects of operational parameters, including working voltage, catalyst dosage, solid-liquid ratio, and micro-arc polarity, on the liquefaction characteristics of microcrystalline cellulose. Experimental results demonstrated that under optimized conditions-anode micro-arc configuration, working voltage of 750 V, catalyst dosage of 1.44 g, and solid-liquid ratio of 6:38-the cellulose conversion rate reached 79.2%, with a liquefied product mass of 4.75 g. Mechanistic analysis revealed that high-energy electrons and hydrogen ions generated by plasma discharge synergistically act on the cleavage of cellulose molecular chains. Under the combined effects of the catalyst and plasma, cellulose molecules are depolymerized into small molecular compounds. Compared with traditional liquefaction processes, this technology exhibits significant advantages in reaction rate and energy efficiency, providing a novel technical route for the efficient conversion of biomass resources.