This paper promotes an ontology-based multi agent system (MAS) framework to facilitate Peer-to-Peer (P2P) service selection with multiple service properties. P2P-based service has emerged as an important new field in the distributed computing arena. It focuses on intensive service sharing, innovative applications and compositions, and, in some cases, high performance orientation. However, one of the remaining challenges for the P2P-based service composition process is how to effectively discover and select the most appropriate peers to execute the service applications when considering multiple properties of the requested services. By introducing an ontology, different ontology-based e-service profiles can be proposed to facilitate handling multiple properties and to enhance the service oriented process in order to achieve the total or partial automation of service discovery, selection and composition. In this paper, we present a conceptual framework for peer selection with a preliminary mathematical model and a selection process, so as to enhance the P2P-based service coordination system and itscomponents.