The present invention relates to the field of mobile communications technologies, and in particular, to a resource allocation method, a service transmission method, and an apparatus, so as to resolve a technical problem of how to coordinately transmit, in a WLAN, a WLAN service and a to-be-offloaded service of a cellular network node. In embodiments of the present invention, resources separately allocated to an AP and the cellular network node are specified, and the AP and the cellular network node are separately notified of an allocation result. In this way, both the AP and the cellular network node transmit data on only the respective allocated WLAN resources, so as to avoid that the WLAN service and the to-be-offloaded service of the cellular network node contend for a channel.