The calibration method, performed on a phased array device, wherein the method initiates a test signal and looping back a plurality of channel responses corresponding to the channel elements through the transmission line to a calibration circuit in the phased array device, wherein each of the channel responses is obtained when one of the channel elements is turned on, and the rest of the channel elements are turned off. The method further calculates a characteristic value corresponding to the transmission line based on the obtained channel responses of the channel elements, and adjusts a channel parameter of one of the channel elements based on the characteristic value of the transmission line.