The capacity problem is one of the main issues in researching the multi-channel IEEE 802.11 wireless networks. In this paper, we analyze the path capacity of the multi-channel wireless networks by estimating the RTS, CTS and the packet loss rate of the wireless links and calculating the average service time of the packet sending. We also analyze the channel assignment and channel switching problems and present the Neighborhood Channel Concentration Degree (NCCD) mechanism which can distribute network load into the available channels and increase the total throughput of the network. We use ns-2 as the simulator to simulate the network throughput using our NCCD and compare with the throughput of the MCR mechanism. The results show that NCCD can significantly increase the network throughput.