An antenna array calibration device and method thereof are provided. The method includes measuring the power total of the antenna array, controlling active components to adjust the antennas to having a maximum amplitude, controlling phase shifters to adjust the antennas to having a random phase, calculating the phase difference between an initial phase and a random phase, calculating the amplitude difference between an initial amplitude and the maximum amplitude, introducing the phase difference, the amplitude difference and the power total of the antenna array into a simultaneous equation of amplitudes and phases to obtain the initial amplitude and the initial phase of the antennas, and adjusting the phase of the antenna array if there is a real number solution of the equation, or otherwise adjusting the phase of the antenna array to another random phase to obtain a real number solution of the equation.