How to manage trust is regarded as a main problem of security issues in P2P overlay networks. Reputationbased trust management is regarded as a promising way to solve the problem. However, in P2P systems, obtaining reputation evidence for building trust relationships is not an easy job. We tackle this problem by employing a scheme for the distribution of reputation evidence, which is based on the swarm intelligence paradigm. Our simulations show that it performs very well in P2P environment. We hope that this method will help move the reputation based trust management closer to fulfilling its promise in P2P networks.