Wireless mesh networks provide an easy deployed and extensible solution to access Internet or communicate with each other for both enterprises and individuals. With the help of multi-channel and multi-radio, wireless mesh network can support more traffic load to meet higher and higher bandwidth requirement in this modern time. There have been researches that focus on channel assignment and routing algorithm for IEEE 802.11 multi-channel environment to achieve better network throughout. However, the data rate and transmission range of 802.11 is limited and is not suitable for a large area metropolitan mesh network deployment. This paper presents a rate-adaption channel assignment and routing algorithm for IEEE 802.16 multi-channel multi-radio network in mesh mode which is expected as the last-mile wireless broadband connectivity. We takes 802.16 TDMA characteristic and modulation/rate adaption into consideration. The Simulation results show that our channel assignment procedure uses fewer channels and better channel utilization than the migrated 802.11 greedy approach. Among the three comparing routing protocols, our protocol performs better in multi-rate 802.16 mesh network and results in higher aggregate throughput.