A gateway device selection method is provided. The method includes: receiving, by a terminal device, a message from a gateway device, where the message includes identification information of the gateway device, and the identification information of the gateway device indicates information about the gateway device; determining, by the terminal device, that the identification information of the gateway device is consistent with preset identification information of a gateway device on the terminal device, and using the gateway device as a selected gateway device; and sending, by the terminal device, a data packet to the selected gateway device. This helps the terminal device correctly identify the gateway device to which the terminal device is to send data.