Wireless Mesh Networks (WMNs) are a wireless broadband access technology based completely on IP technologies and has thus rapidly become a means for broadband access with the characteristics of high capacity, high speed and wide coverage. For trusted roaming in WMNs, the configuration of the access platforms must be checked first before access to the network can continue, and only those platforms whose configurations meet the security requirements of the network can be allowed to access the network. It is also required that mobile nodes complete access authentication not only in a timely manner, but also in a way in which the identities of the mobile nodes are well protected. In this paper, we propose a trusted roaming protocol that are based on several technologies such as hierarchical network model, elliptic curve cryptography (ECC), trust evaluation, grey relevance analysis, etc. to ensure the security of roaming in WMNs. We also show the security properties of the proposed protocol through formal analysis and the performance by presenting some simulation results.