A communication method and device using beamforming in a wireless communication system are disclosed. A base station determines according to a predetermined trigger condition and a channel state of a terminal whether to enable a beam overlap mode using an overlap beam in which a plurality of unitary beams of the base station are overlapped, selects one or more best beams from among the plurality of unitary beams if it is determined that the beam overlap mode is not enabled, and transmits or receives a signal for the terminal through the selected best beams. If it is determined that the beam overlap mode is enabled, the base station forms the overlap beam in which the plurality of unitary beams of the base station are overlapped by adjusting beamforming coefficients of a beamforming unitary and transmits or receives a signal for the terminal through the overlap beam.