Routing protocols are the key factors which determine the communication performance in the multi-interface wireless mesh networks. The existing routing protocols can not capture the channel interference accurately. In order to utilize the multi-interface technology to reduce the interference and improve the network throughput, this paper presented a novel routing metric for multi-interface wireless mesh networks. This metric integrated both the channel similarity and the link load to measure the route quality. Furthermore, this paper applied this routing metric to the AODV routing protocol which formed a new routing protocol. The simulation results show that the new protocol outperforms the original AODV protocol in terms of the average throughput, transmission rate and end-to-end delay.