A method for feeding back Channel State Information, CSI, comprising steps of: dividing a plurality of antenna ports into a plurality of groups of antenna ports; wherein the method further comprises: configuring for each group of the plurality of groups of antenna ports a same intra-group codebook set consisting of a plurality of intra-group precoding matrices, allocating for each group of the plurality of groups of antenna ports one reference signal corresponding to each reference resource of a plurality of reference resources, and configuring for each antenna port in each group of the plurality of groups of antenna ports a precoded reference signal acquired after a precoding operation using the intra-group precoding matrices, a number of the reference resources corresponding to a number of the intra-group precoding matrices in the intra-group codebook set, and a number of the reference signals corresponding to each reference resource corresponding to a number of groups of inter-group antenna ports; transmitting the precoded reference signal to a User Equipment, UE, via each antenna port; and receiving the CSI fed back by the UE based on measurement on the reference signal; wherein the step of dividing the plurality of antenna ports into the plurality of groups of antenna ports comprises dividing every M antenna ports in each column of antenna ports in a vertical direction into one group, each column of antenna ports being divided into a same number of groups and M representing a predetermined number of antenna ports in each group; wherein the reference resource is a Channel State Information-Reference Signal, CSI-RS, resource, and the reference signal is a CSI-RS; a number of the CSI-RS resources is the same as a number of the intra-group precoding matrices in the intra-group codebook set, a number of the CSI-RSs corresponding to each CSI-RS resource is the same as a number of groups of the inter-group antenna ports; and the CSI-RSs corresponding to a same CSI-RS resource allocated for the plurality of groups of antenna ports are precoded with a same intra-group precoding matrix so as to form beams in a same direction, the CSI-RSs corresponding to different CSI-RS resources allocated for a same group of antenna port are precoded with different intra-group precoding matrices so as to form beams in different directions, and the beams formed by the different intra-group precoding matrices evenly cover an entire angular range in a vertical direction. dividing a plurality of antenna ports into a plurality of groups of antenna ports; wherein the method further comprises: configuring for each group of the plurality of groups of antenna ports a same intra-group codebook set consisting of a plurality of intra-group precoding matrices, allocating for each group of the plurality of groups of antenna ports one reference signal corresponding to each reference resource of a plurality of reference resources, and configuring for each antenna port in each group of the plurality of groups of antenna ports a precoded reference signal acquired after a precoding operation using the intra-group precoding matrices, a number of the reference resources corresponding to a number of the intra-group precoding matrices in the intra-group codebook set, and a number of the reference signals corresponding to each reference resource corresponding to a number of groups of inter-group antenna ports; transmitting the precoded reference signal to a User Equipment, UE, via each antenna port; and receiving the CSI fed back by the UE based on measurement on the reference signal; wherein the step of dividing the plurality of antenna ports into the plurality of groups of antenna ports comprises dividing every M antenna ports in each column of antenna ports in a vertical direction into one group, each column of antenna ports being divided into a same number of groups and M representing a predetermined number of antenna ports in each group; wherein the reference resource is a Channel State Information-Reference Signal, CSI-RS, resource, and the reference signal is a CSI-RS; a number of the CSI-RS resources is the same as a number of the intra-group precoding matrices in the intra-group codebook set, a number of the CSI-RSs corresponding to each CSI-RS resource is the same as a number of groups of the inter-group antenna ports; and the CSI-RSs corresponding to a same CSI-RS resource allocated for the plurality of groups of antenna ports are precoded with a same intra-group precoding matrix so as to form beams in a same direction, the CSI-RSs corresponding to different CSI-RS resources allocated for a same group of antenna port are precoded with different intra-group precoding matrices so as to form beams in different directions, and the beams formed by the different intra-group precoding matrices evenly cover an entire angular range in a vertical direction.