Space-borne reflector antennas have gain wide application for their unique advantages, and if they are fed by array antennas, the beam can be controlled freely. However, for the factors of extremely changing space temperature, repeated development, assembly errors and so on, the beams of deployable antennas will be deteriorated. To achieve anticipative performance, beam compensation should be performed. In the study, influences of the reflector's global, local and mixed deformations on the antenna performances are investigated by physical optics (PO) method, and the conjugate field matching (CFM) method, an easy and time-efficient method, is employed to compensate the beam degradation. The effectiveness of beam compensation by CFM for different kinds of reflector surface deformations are researched and compared. The results show that the beam pointing accuracy can be well compensated for all types of deformations, while the compensation effect is good under global deformations, but bad under local deformations.