The present disclosure provide a wireless local area network discovery and selection method, device, and system, and a terminal. The method includes sending a registration request to a wireless local area network discovery and selection device when packet switched data is initiated to a cellular network. A notification message sent by the wireless local area network discovery and selection device is received. The notification message is sent when the wireless local area network discovery. The selection device determines that a wireless local area network needs to be used to offload the packet switched data in the cellular network. The notification message carries access parameter information.