Depolymerization of lignin to produce high yield lignin oil is one of the prospective methods to achieve the sustainable and economic development for human society. Molybdenum-based sepiolite (Mo/SEP) catalyst presented a promising performance for lignin depolymerization under supercritical ethanol (LDSE). Herein, the influence of reductive treatments for calcined Mo/SEP (C-Mo/SEP) catalyst on lignin depolymerization was systematically investigated under supercritical ethanol. Two reduced catalysts N-Mo/SEP and H-Mo/SEP was obtained respectively through the reduction process by NaBH4 and 10 vol % H-2/N-2 flow. The characterizations such as N-2 adsorption-desorption, SEM, XRD, FTIR, XPS, NH3-TPD, and Py-FTIR were employed to investigate the variation of microcosmic structure and property of Mo/SEP affected by reductive treatments. The results exhibited that reduction treatment optimized the distributions of Mo5+ species and B/L acidic sites of Mo/SEP catalysts. During the LDSE process at 290 degrees C under N-2 atmosphere for 3 h, lignin oil produced over N-Mo/SEP catalyst gave a higher heating value of 34.92 MJ/kg, which slightly decreased from 36.07 MJ/kg that was obtained over C-Mo/SEP. But N-Mo/SEP catalyst generated the highest yields of lignin oil (112.0%) and petroleum ether soluble (PES) product (74.6%). According to the GC-MS results, the possible mechanism of N-Mo/SEP catalytic LDSE was proposed. The synergistic effect between Mo5+ species and B/L acid sites promoted the cracking of the C-aryl-OCH3 bond, and the moderate acid amounts enhanced the alkylation reaction.