An antenna device and a method for calibrating an antenna device are provided, and the method includes: transmitting or receiving a signal by a first antenna unit and a second antenna unit; receiving the signal from the first antenna unit and the second antenna unit or transmitting the signal to the first antenna unit and the second antenna unit by a probe, wherein the first antenna unit and the second antenna unit are at a first distance from the probe respectively; and calibrating the first antenna unit and the second antenna unit according to a beat frequency of the signal corresponding to the first distance.