A communication parameter determination method, and a WLAN communication method and device, comprising: a base station determines a first communication parameter used by a first mobile terminal for communication in a WLAN, the first communication parameter representing a first waiting time of the first mobile terminal in the WLAN from the time of determining that the channel is idle to the time of starting to communicate, and the first waiting time being less than a second waiting time of a second mobile terminal in the WLAN from the time of determining that the channel is idle to the time of starting to communicate; the base station transmits the determined first communication parameter to the first mobile terminal. Accordingly, the first mobile terminal about to switch from a cellular network to the WLAN receives the first communication parameter transmitted by the base station; and after accessing the WLAN, the first mobile terminal uses the first communication parameter to communicate in the WLAN. The solution provided in an embodiment of the present invention improves the WLAN communication quality for a mobile terminal that has switched from a cellular network to a WLAN.