Common Channel Framework (CCF), a multichannel mechanism proposed in 802.11s, extends traditional DCF mechanism and is fully compatible with traditional 802.11 WLAN. According to the characteristics of CCF reaching maximum throughput in the state of no assigning common channel to transmit data, a method to improve the performance of CCF is proposed. In one collide field, under the condition of fixed parameters including number of stations, data rate, payload in data frame, without enough channels the improved CCF can also transfer from the state of assigning common channel to the state of no assigning common channel to transmit date and then reach much more throughput.