The present disclosure discloses a method, an apparatus, a device, and a system for antenna alignment. The method includes: performing, according to a target preset condition, adjustment processing on a phase and an amplitude of a signal that is transmitted by each antenna unit of a first antenna, and the second antenna is located within a coverage scope of the target beam; and determining that a difference between a horizontal angle of the target beam and a mechanical horizontal angle of a current mechanical location of the first antenna is a horizontal angle, that needs to be adjusted, of the first antenna, adjusting the mechanical horizontal angle and the mechanical pitch angle of the first antenna according to the horizontal angle that needs to be adjusted and the pitch angle that needs to be adjusted.