NOVELTY - Refining biodiesel oil byproduct crude glycerol comprises (i) adding diluent to crude glycerol byproduct for dilution, (ii) taking diluted crude glycerol, neutralizing, heating, stirring, subjecting to centrifugal separation to obtain a liquid layer, degassing and drying to obtain desalted glycerol, (iii) adding sodium oxalate, stirring uniformly, controlling the temperature and the mixing time, filtering to obtain glycerol mixture, (iv) distilling by heating at atmospheric pressure to distill methanol and water and distilling again and (v) adding activated carbon twice and bleaching.    USE - The method is useful for refining biodiesel oil byproduct crude glycerol (claimed).    ADVANTAGE - The method: is simple, and produces high yield of glycerol with good quality and purity.    DETAILED DESCRIPTION - Refining biodiesel oil byproduct crude glycerol comprises (i) adding 10-30 wt.% diluent to the crude glycerol byproduct resulted in biodiesel oil production for dilution, (ii) taking diluted crude glycerol, neutralizing until the pH is 5-7, heating to 70-80 degrees C, stirring for 50-60 minutes, subjecting to centrifugal separation to obtain a liquid layer, in which the upper layer is the crude fatty acid, the middle layer is glycerol, water and small amount of methanol, the lower layer is salt and soap byproduct, taking the middle layer mixture, degassing in a rotary evaporator and drying to obtain desalted glycerol, (iii) adding 0.02-0.03 wt.% sodium oxalate to the desalted glycerol, stirring uniformly, controlling the temperature at 70-80 degrees C and the mixing time of 30-70 minutes, filtering to remove the impurity to obtain glycerol mixture, (iv) carrying out distillation by heating at atmospheric pressure to distill methanol and water, and distilling by heating at 164-204 degrees C to obtain semi-finished product of glycerol, and (v) adding 0.3-1.3 wt.% activated carbon to the semi-finished product of glycerol twice, bleaching at 70-80 degrees C for 30-60 minutes to obtain the finished product.