The problem of sharing data in peer-to-peer environment has received considerable attention in recent years. However, knowledge sharing in peer architectures has received very little attention. This paper proposes a framework for query reformulation in peer architectures. We first consider a mapping language based on a particular description logic that includes class connectors. Then a set of rules are proposed for building graphs. Because the axioms in a knowledge base have different properties, our graph generation algorithm classifies the generated graphs into four sets (Ugraph, Bgraph, Cgraph and Dgraph). Furthermore, based on the properties of the unification nodes, our algorithms can reformulate each kind of atom in a special way. Finally we do extensive simulation experiments and simulation results show that the proposed method has better performance than those of Mork’s [8].