Disclosed in the present invention are a channel state information (CSI) feedback method, a precoding method, a terminal and a base station. The channel state information (CSI) feedback method disclosed in the present invention comprises: a terminal selects a channel state information-reference signal (CSI-RS) resource or a CSI-RS port on a convention subband from among a CSI-RS resource set as configured in a base station according to downlink channel information; the terminal measures a channel quality indicator (CQI) according to the selected CSI-RS resource or CSI-RS port and a precoding matrix set corresponding to the selected CSI-RS resource or CSI-RS port, wherein the precoding matrix set includes one or more preceding matrices, and a physical resource on the convention subband corresponds to a precoding matrix in the precoding matrix set; and the terminal feeds back the CQI and indication information of the selected CSI-RS resource or CSI-RS port. According to the present invention, the matching degree between CSI and channel state may be improved.