TACAN phased-array antenna is a large antenna of TACAN beacon. Because the antenna should be formed into a rotating nine-lobed cordate pattern, real-time control must be performed for the phase of the phased-shifter controlling the phase of radiated signal. The veracity of the antenna pattern is determined by the initial phase of the phased-shifter, so, only when phase calibration is done, can TACAN phased-array antenna work normally. In this paper, based on the analysis of the direction pattern forming principle and phase calibration method for TACAN phased-array antenna, and by adopting Fourier theory and vector accumulation principle, a realizable phase calibration algorithm on the basis of vector accumulation is put forward. By using this algorithm, the times of calculation can be reduced, the calibration speed is enhanced and the requirements for hardware are moderated. The experiment result shows that this algorithm is reasonable and effectual in precise phase calculation, fast in phase calibration. And this algorithm has been successfully applied in the TACAN phased-array antenna.