A method of providing an optimal transmission or reception (Tx/Rx) beam in a beamforming system. The method includes receiving a reference signal and selecting an optimal Tx/Rx beam that guarantees an optimal channel environment based on the received reference signal determining a possibility of occurrence of a Tx/Rx beam mismatch between the selected optimal Tx/Rx beam and a Tx/Rx beam used for transmitting information on the selected optimal Tx/Rx beam; and when there is the possibility of the occurrence of the Tx/Rx beam mismatch, performing at least one of widening a beam width of the Tx/Rx beam, increasing a number of Tx/Rx beams, reducing a period of a beam selection operation for selecting the optimal Tx/Rx beam, and reducing a transmission period of the reference signal. Other embodiments including a beamforming system are also disclosed.