Aiming at fitting for complexity and dynamic network management activities, Policy-Based Network Management (PBMN) is brought forward. As the core of PBMN, nowadays, Policy Language has become a conjunct focus in both network management and Multi-Agent computing fields. In Multi-Agent Based network management system (NMS), a management policy goes by the name of a Agent requesting another one to realize a concept, or a Agent making another one change its states. Typical policy languages includes KAoS, Rei, Ponder, but these policy languages share a common deficiency in logic-based expression and calculation capacities that is important for intelligent network management. So in this paper we make use of the expansion Description Logic to describe semantic of management policies in order to enhance its logic-based calculation capacities.