NOVELTY - A mizoribine is purified by (1) adding acid into mizoribine in fermentation liquor, adjusting pH to 2.5-5.5, adding flocculating agent, filtering to obtain coarse filtrate; (2) putting obtained coarse filtrate in bleaching column, purifying at flow rate of 0.5-2 times of column bed volume/hour, collecting effluent to obtain bleached solution in which filler used in bleaching column is cation exchange resin; and (3) adding alkaline solution in obtained bleached solution, adjusting pH to 7.5-10.5, loading into adsorption column, and eluting with pure water.    USE - Purification of mizoribine (claimed).    ADVANTAGE - Purification process is simple and produces high yield. Product has good stability and uniform particles.    DETAILED DESCRIPTION - A mizoribine is purified by (1) adding acid into mizoribine in fermentation liquor, adjusting pH to 2.5-5.5, adding flocculating agent, filtering to obtain coarse filtrate; (2) putting obtained coarse filtrate in bleaching column, purifying at flow rate of 0.5-2 times of column bed volume/hour, collecting effluent to obtain bleached solution in which filler used in bleaching column is cation exchange resin; (3) adding alkaline solution in obtained bleached solution, adjusting pH to 7.5-10.5, loading into adsorption column, eluting with pure water at flow rate of 0.5-2 times of column bed volume/hour until effluent is neutral, eluting acidic eluent, collecting effluent to obtain enriched solution in which filler used in adsorption column is strong alkaline anion exchange resin; (4) adding alkaline solution in obtained enriched solution, adjusting pH to 8-10, loading into adsorption column, eluting with pure water at flow rate of 0.5-2 times of column bed volume/hour until effluent is neutral, eluting acidic eluent, collecting effluent to obtain secondary enriched solution in which filler used in adsorption column is strong alkaline anion exchange resin; (5) adding n times-enriched solution in bleaching column, purifying at flow rate of 0.5-2 times of column bed volume/hour, collecting effluent to obtain secondary bleached solution in which filler used in bleaching column is strong alkaline anion exchange resin; (6) decompressing obtained secondary bleached solution, cooling to crystallize, filtering, washing filter cake with absolute ethanol, vacuum drying at 40 degrees C to obtain mizoribine powder; and (7) dissolving obtained mizoribine powder in pure water at 85-90 degrees C to obtain mizoribine solution, adding boiling absolute ethanol, stirring, cooling to crystallize, filtering, washing filter cake with absolute ethanol, and vacuum drying at 40 degrees C.