The present invention provides a method for obtaining channel state information required for beamforming, comprising: estimating current channel state information according to a received signal; predicting future channel state information which is expected to be used by a transmitter in the next beamforming based on the current channel state information and historical channel state information; reading previous channel state information used by the transmitter in the current beamforming; determining feedback information based on the future channel state information and the previous channel state information; and sending the feedback information to the transmitter. The present invention further provides a method for performing beamforming, comprising: receiving feedback information from a receiver; reading previous channel state information used in the last beamforming; reconstructing channel state information based on the feedback information and the previous channel state information; and performing beamforming according to the reconstructed channel state information.