Semantic routing is one of key parts in P2P routing researches. The intelligent search mechanisms support flexible semantic expression but hold low scalability and recall rate. Contrastively, semantic overlay network is scalable but either is difficult to organize or take too large maintenance spending. This paper proposes a new P2P semantic routing model in which node array is organized by match path and probability balance tree, and then an approximately balance distributed structure is obtained. All nodes will take routing decision according to query content while limiting maintenance spending to relative low level. The model supports flexible semantic search and high scalability, and ensures that each node can reach any corner of the network. The model runs with no center service in which all nodes simultaneously take index storage and data storage, and forward task to share system’s running load by only maintaining a little local information.