A switching method and a terminal device, which relate to the communications field. The switching method comprises: establishing, by a terminal device, a first packet data network PDN connection in a long term evolution LTE access network; switching, by the terminal device, the first PDN connection from the LTE access network to a wireless local area network WLAN access network; establishing, by the terminal device, a second PDN connection in the LTE access network, so that the terminal device is in a registered state in the LTE network; and switching, by the terminal device, the first PDN connection or a third PDN connection established in the WLAN access network, to the LTE access network.