An antenna switching system, comprising a radio-frequency transceiver circuit including a radio-frequency transceiver which is connected to a modem of a mobile terminal, a primary antenna, and parasitic antennas, wherein the primary antenna is connected to the radio-frequency transceiver circuit, and further comprising: a switch circuit, configured to connect, when it is required to use a parasitic antenna to receive or send a radio-frequency signal, the parasitic antenna and the radio-frequency transceiver circuit; the switch circuit is further configured to: when only the primary antenna is used to receive or send a radio-frequency signal, cut off a connection between the parasitic antennas and the radio-frequency transceiver circuit, and ground the parasitic antennas, and characterized in that the antenna switching system further comprises the modem, wherein the modem is configured to receive a multichannel prompt, determine, according to the multichannel prompt, frequency bands in which multiple channels of radio-frequency signals that need to be received, and generate a switching instruction according to the multichannel prompt, where the switching instruction specifies parasitic antennas to be used, and the switch circuit is specifically configured to: when a switching instruction sent by the modem of the mobile terminal is received, connect a parasitic antenna specified by the switching instruction to the radio-frequency transceiver circuit in order to implement that a channel of the multiple channels of the radio-frequency signals is received or sent by means of the parasitic antenna specified by the switching instruction. a switch circuit, configured to connect, when it is required to use a parasitic antenna to receive or send a radio-frequency signal, the parasitic antenna and the radio-frequency transceiver circuit; the switch circuit is further configured to: when only the primary antenna is used to receive or send a radio-frequency signal, cut off a connection between the parasitic antennas and the radio-frequency transceiver circuit, and ground the parasitic antennas, and characterized in that the antenna switching system further comprises the modem, wherein the modem is configured to receive a multichannel prompt, determine, according to the multichannel prompt, frequency bands in which multiple channels of radio-frequency signals that need to be received, and generate a switching instruction according to the multichannel prompt, where the switching instruction specifies parasitic antennas to be used, and the switch circuit is specifically configured to: when a switching instruction sent by the modem of the mobile terminal is received, connect a parasitic antenna specified by the switching instruction to the radio-frequency transceiver circuit in order to implement that a channel of the multiple channels of the radio-frequency signals is received or sent by means of the parasitic antenna specified by the switching instruction. when only the primary antenna is used to receive or send a radio-frequency signal, cut off a connection between the parasitic antennas and the radio-frequency transceiver circuit, and ground the parasitic antennas, and characterized in that the antenna switching system further comprises the modem, wherein the modem is configured to receive a multichannel prompt, determine, according to the multichannel prompt, frequency bands in which multiple channels of radio-frequency signals that need to be received, and generate a switching instruction according to the multichannel prompt, where the switching instruction specifies parasitic antennas to be used, and the switch circuit is specifically configured to: when a switching instruction sent by the modem of the mobile terminal is received, connect a parasitic antenna specified by the switching instruction to the radio-frequency transceiver circuit in order to implement that a channel of the multiple channels of the radio-frequency signals is received or sent by means of the parasitic antenna specified by the switching instruction.