Abstract: Optimization of surgical treatment of biliary dilatation (BD) depends on reasonable clinical classification and standardized classificationbased treatment strategy. Due to increasing limits and defects of classic Todani classification, a new classification named Dong-classification has been proposed, which was based on a large series analysis from a single referral center. Some important parameters including anatomical location and range of BD, pathogenic factors, and different surgical managements were main considerations in the new classification. After practical application and evaluation, Dong-classification has been improved step by step. It is believed that Dongclassification may contribute to improving surgical treatment decision and selecting reasonable operative plan.