The invention provides a wireless terminal antenna performance testing system which comprises an anechoic chamber, a power detector and a digital analog converter, wherein the anechoic chamber comprises a shielding box, a wave absorbing material mounted on the inner wall of the shielding box as well as measuring antennas; the power detector is connected with the measuring antennas. According to the wireless terminal antenna performance testing system provided by the embodiment of the invention, by means of the power detector and the digital analog converter, a task for converting a radio-frequency signal into direct read data, namely, a digital signal can be finished; a special measuring instrument is omitted, a comprehensive measuring instrument is not required to participate in the whole process, and the configuration cost of the testing system is reduced; meanwhile, the antenna performance is accurately tested under the shielding condition in a non-signaling mode, the waiting time for connection establishing between the measuring instrument and a to-be-measured wireless terminal is saved, outside electromagnetic interference is reduced, the testing efficiency and the accuracy are improved, and the system is particularly applicable to testing of the antennas of a wireless terminal.