Provided is a process for purifying a vancomycin wet body, comprising: dissolving a wet body obtained from a microorganism-fermented solution containing vancomycin into a water soluble solvent to a concentration of about 1 to 40 g/L and carrying out reverse osmosis filtration; and carrying out lyophilization of the filtered vancomycin. The process for purifying a vancomycin wet body provides high-purity vancomycin, while avoiding degradation of stability during a drying step.