A transmit antenna switching method, applied to a terminal device and comprising: when the terminal device is in a dual-network connected state, determining a first network used to transmit control plane data and a second network only used to transmit user plane data; determining, based on a transmit antenna used by the first network, a first transmit mode for switching a sounding reference signal SRS antenna operating in the second network; and performing the SRS antenna switching based on the first transmit mode by using a first antenna set, wherein the dual-network connected state is that the terminal device is simultaneously connected to the first network and the second network; the first transmit mode comprises a quantity of antennas for performing the SRS antenna switching in the second network; and the first antenna set is all antennas used for the dual-network connected state comprised in the terminal device except the transmit antenna used by the first network; wherein the determining, based on a transmit antenna used by the first network, a first transmit mode for switching a sounding reference signal SRS antenna operating in the second network comprises: determining, based on the transmit antenna used by the first network, the first antenna set used for the SRS antenna switching of the terminal device; and determining, based on the first antenna set, the first transmit mode for the SRS antenna switching of the terminal device; characterized in that the determining, based on the first antenna set, the first transmit mode for the SRS antenna switching of the terminal device comprises: determining, based on antenna information in the first antenna set, the first transmit mode for the SRS antenna switching, the antenna information including whether an antenna can be used as a transmit antenna of the second network; wherein, the first transmit mode is further used to indicate whether the second network supports the SRS antenna switching, and a mode of the SRS antenna switching supported by the second network. when the terminal device is in a dual-network connected state, determining a first network used to transmit control plane data and a second network only used to transmit user plane data; determining, based on a transmit antenna used by the first network, a first transmit mode for switching a sounding reference signal SRS antenna operating in the second network; and performing the SRS antenna switching based on the first transmit mode by using a first antenna set, wherein the dual-network connected state is that the terminal device is simultaneously connected to the first network and the second network; the first transmit mode comprises a quantity of antennas for performing the SRS antenna switching in the second network; and the first antenna set is all antennas used for the dual-network connected state comprised in the terminal device except the transmit antenna used by the first network; wherein the determining, based on a transmit antenna used by the first network, a first transmit mode for switching a sounding reference signal SRS antenna operating in the second network comprises: determining, based on the transmit antenna used by the first network, the first antenna set used for the SRS antenna switching of the terminal device; and determining, based on the first antenna set, the first transmit mode for the SRS antenna switching of the terminal device; characterized in that the determining, based on the first antenna set, the first transmit mode for the SRS antenna switching of the terminal device comprises: determining, based on antenna information in the first antenna set, the first transmit mode for the SRS antenna switching, the antenna information including whether an antenna can be used as a transmit antenna of the second network; wherein, the first transmit mode is further used to indicate whether the second network supports the SRS antenna switching, and a mode of the SRS antenna switching supported by the second network.