At least three known standards are normally required for the full two-port test fixture calibration in vector network analyzers (VNA). In this paper, a calibration procedure using only one standard, based on establishing two hypothetical symmetrical fixtures using triple-through method, is shown. The results using th e calibrating method to subtract the influence of fixtures are in accord with th e directly measured data of the device-under-test (DUT) without the fixtures ver y well, which shows that the proposed method is very simple and accurate.