Embodiments of the present invention relate to the communication field and provide an array antenna. The array antenna includes: an antenna body, which is a multi-beam antenna, a single-beam antenna without grating lobes, or a single-beam antenna with grating lobes and transmits or receives a beam set by centering on the antenna body, where the beam set includes at least one beam; a planar reflection board, configured to reflect the beam set transmitted or received by the antenna body; and an adjusting unit, connected to the antenna body and/or the planar reflection board, and configured to adjust a relative position between the planar reflection board and the beam set of the antenna body so that the beam set of the antenna body can be transmitted or received in any direction after being reflected by the planar reflection board.