The present invention discloses a cellular-network-assisted wireless local area network (WLAN) channel switch announcement method, including the following steps: before a wireless network access point (AP) performs channel switching, delivering channel switch announcement signaling to correlated user equipment in a broadcast manner, and sending channel switch announcement request signaling to a cellular network base station that also serves the user equipment; after the cellular network base station receives the channel switch announcement request signaling, sending the channel switch announcement signaling to user equipment in an idle mode by using a cellular link air interface; and performing, by the WLAN AP, channel switching within a predetermined time, and following, by user equipment that directly acquires channel switch information by receiving the channel switch announcement signaling and user equipment that acquires channel switch information by using the cellular network base station, the WLAN AP and performing channel switching.