The invention provides an antenna performance control system which is applied to mobile communication equipment equipped with a proximity sensor. The system comprises an RSSI (received Signal Strength Indicator) detection module and a control module, wherein the RSSI detection module is used for detecting the RSSI value of a radio signal received by a mobile communication equipment in real time, and the control module is used for sending a control instruction to an antenna performance adjustment unit of the mobile communication equipment when the RSSI value of the received signal is attenuated when a human body approach in the connected call of the mobile communication equipment as compared with the RRSI value before the call is connected, and the antenna of the mobile communication equipment can be adjusted from first antenna performance to second antenna performance. The invention also provides an antenna performance control method. The invention can improve communication quality influenced by the approaching of a human body during a phone call.