The present invention provides a hybrid-beamforming method for supporting multi-ranks, a beam estimation method and devices for supporting the methods. A hybrid-beamforming performance method for supporting multi-ranks in a wireless access system, according to one embodiment of the present invention, can comprise the steps of: detecting, by a transmission end, at least two analog beam candidates having a channel gain greater than or equal to a reference value; pre-compensating analog beam coefficients for at least two analog beam candidates such that one analog beam among the at least two analog beam candidates includes at least two digital beams; resetting digital PMI coefficient values for at least two digital beams so as to reflect the pre-compensated analog beam coefficients; and transmitting a multi-rank signal by using the pre-compensated analog beam coefficients and the reset digital PMI coefficient values. At this time, analog beamforming and digital beamforming are combined such that hybrid-beamforming can be performed.