A method for calibrating a phased array antenna, wherein the phased array antenna comprises a plurality of service antenna elements and a plurality of calibration antenna elements that are deployed independently of the plurality of service antenna elements, the plurality of service antenna elements are grouped into a plurality of antenna subarrays based on the plurality of calibration antenna elements, and one calibration antenna element corresponds to one antenna subarray; and the method comprises: performing the following operations on a test signal transmitted through any transmit channel n in the phased array antenna, to obtain a calibration signal corresponding to the transmit channel n: transmitting any test signal through the transmit channel n, wherein the test signal is radiated by a service antenna element n corresponding to the transmit channel n and is received by a calibration antenna element in the phased array antenna; obtaining N coupling signals received by N calibration antenna elements coupled to the service antenna element n, wherein N is greater than or equal to 2 and is less than or equal to a total quantity of calibration antenna elements in the phased array antenna; and performing delay weighting on the N coupling signals based on relative positions of the service antenna element n and each of the N calibration antenna elements to obtain N calibration signals aligned in time domain; and combining the N calibration signals into the calibration signal corresponding to the transmit channel n; obtaining calibration signals corresponding to all transmit channels in the phased array antenna; and compensating for amplitudes and/or phases of the transmit channels based on a difference between the amplitudes and/or the phases of the calibration signals corresponding to the transmit channels in the phased array antenna, so that the transmit channels in the phased array antenna have equal amplitudes and/or phases. performing the following operations on a test signal transmitted through any transmit channel n in the phased array antenna, to obtain a calibration signal corresponding to the transmit channel n: transmitting any test signal through the transmit channel n, wherein the test signal is radiated by a service antenna element n corresponding to the transmit channel n and is received by a calibration antenna element in the phased array antenna; obtaining N coupling signals received by N calibration antenna elements coupled to the service antenna element n, wherein N is greater than or equal to 2 and is less than or equal to a total quantity of calibration antenna elements in the phased array antenna; and performing delay weighting on the N coupling signals based on relative positions of the service antenna element n and each of the N calibration antenna elements to obtain N calibration signals aligned in time domain; transmitting any test signal through the transmit channel n, wherein the test signal is radiated by a service antenna element n corresponding to the transmit channel n and is received by a calibration antenna element in the phased array antenna; obtaining N coupling signals received by N calibration antenna elements coupled to the service antenna element n, wherein N is greater than or equal to 2 and is less than or equal to a total quantity of calibration antenna elements in the phased array antenna; and performing delay weighting on the N coupling signals based on relative positions of the service antenna element n and each of the N calibration antenna elements to obtain N calibration signals aligned in time domain; and combining the N calibration signals into the calibration signal corresponding to the transmit channel n; obtaining calibration signals corresponding to all transmit channels in the phased array antenna; and compensating for amplitudes and/or phases of the transmit channels based on a difference between the amplitudes and/or the phases of the calibration signals corresponding to the transmit channels in the phased array antenna, so that the transmit channels in the phased array antenna have equal amplitudes and/or phases.