The invention discloses a production method of pure cubilose. The production method comprises the following steps of: firstly, checking and accepting raw materials, namely, selecting light hair or medium hair crude cubilose raw materials; secondly, sterilizing, namely, disinfecting and sterilizing the raw materials by using ultraviolet rays; thirdly, primarily removing impurities, namely scrubbing black dots on the raw materials, removing the impurities on the raw materials; fourthly, soaking for swelling; fifthly, rinsing and picking hairs and removing the impurities, wherein the picking and washing are carried out for three times; sixthly, checking. According to the production method, the raw materials are finely checked and accepted, the sterilization and primary impurity-removing procedures are added, the soaking for swelling and the three-time picking and washing are carried out so that the cubilose is high in purity, the effect of the cubilose is ensured, and the cubilose is pure without foreign tastes, and is relatively good in mouth feel.