The present invention discloses a method for feeding back channel state information, a method for receiving channel state information, and a device. The method includes: selecting, by a terminal, a precoding matrix from a preset codebook subset for each subband in N subbands according to a configured reference signal, where each precoding matrix in the codebook subset is identified by a first PMI, a second PMI, and a third PMI that is used to indicate a phase relationship, first PMIs corresponding to the precoding matrices selected by the terminal for all subbands in the N subbands are the same, the precoding matrix selected for each subband in the N subbands corresponds to one second PMI, and third PMIs corresponding to the precoding matrices for all subbands in the N subbands are the same; and reporting, by the terminal, the first PMI, the second PMI, and the third PMI.