In text document sharing Peer-to-Peer (P2P) applications, similar peers are peers which share documents about the same topic. Finding similar peers can benefit document retrieval in P2P systems. In this paper, we suggested an effective resource description based approach to find similar peers. By combining the topic model (an extension of language model) technique and fuzzy set theory, we solve the key problems about resource description generation and peer similarity calculation. Experiments performed on the standard data sets prove that our approach is effective. Especially, comparing with the traditional approach, experimental results in the simulated P2P environment manifest that our approach works much better when only local information is available.