A method of recovering aqueous N-Methylmorpholine-N-Oxide solution used in production of Lyocell fiber comprises following steps. Bleach means for decoloring coloration in aqueous NMMO solution via alternate blow-mixing adsorption mode and static suspending adsorption mode reiteration. Filtration means for purifying the activated carbon powder and impurities by two filtering stages of first coarse filtering stage and second fine filtering stage. Concentration means for intensifying aqueous NMMO solution to obtain a condensed aqueous solution without NMMO solvent and a concentrated aqueous solution with NMMO solvent respectively by a sequential multi-stage evaporating system. Refinement means for purifying aqueous NMMO solution with promoting purity of concentrated aqueous solution to obtain required recovered aqueous solution by adding suitable agents in the redox reactions involved. Owing to streamlining and simplicity, the method not only has better competitiveness from promoted recovery cost, efficiency and quality but also meets regulations of environmental protection.