A method for feeding back channel state information and user equipment are provided in the present invention, which relates to the digital communication field; and they solve the problem of lacking a mechanism of reporting overall and effective channel state information in a SU-MIMO and MU-MIMO dynamic switching system. The method includes: in a single transmission mode, UE sends the channel state information to a network side, wherein the channel state information includes information indicating a transmission layer with the best channel quality. Technical schemes provided in the present invention are applied to the LTE system and LTE-A system.