The present invention is applicable to the field of mobile terminals and provides an antenna switching system and method. The antenna switching system includes a radio-frequency transceiver circuit, a primary antenna, and a parasitic antenna, where the primary antenna is connected to the radio-frequency transceiver circuit, and further includes a switch circuit, configured to connect, when the parasitic antenna is used to receive or send a radio-frequency signal, the parasitic antenna and the radio-frequency transceiver circuit. If the parasitic antenna is grounded, the parasitic antenna may be configured to spread a spectrum. In addition, when carrier aggregation is needed, the parasitic antenna is connected to the radio-frequency transceiver circuit, so as to become an independent receive or transmit antenna.