A channel state information feedback method, wherein a basis matrix that comprises sparsity of channel state information, CSI in a frequency domain and a space domain is pre-synchronized with a base station, BS, and the method comprises: receiving pilot information sent by the BS; determining, according to the pilot information, a CSI information matrix that comprises information about the frequency domain and the space domain of CSI; determining to-be-transmitted data by using the CSI information matrix, wherein the step of determining to-be-transmitted data by using the CSI information matrix comprises: performing compressive sensing processing on the CSI information matrix to obtain the to-be-transmitted data; and feeding back the to-be-transmitted data to the BS, so that the BS restores the corresponding CSI information from the to-be-transmitted data by using the basis matrix that is pre-synchronized with UE and comprises the sparsity of the CSI in the frequency domain and the space domain; characterized in that the method further comprises: receiving a training sequence, of a period of time, sent by the BS; measuring and calculating a corresponding CSI channel matrix sequence according to the training sequence, wherein each CSI channel matrix in the measured and calculated CSI channel matrix sequence is a matrix that comprises information about a frequency domain and a space domain of CSI; if an initialized basis matrix is given, calculating a sparse vector sequence corresponding to a sequence comprising column vectors corresponding to each CSI channel matrix; determining, according to the sparse vector sequence, the basis matrix that comprises the sparsity of the CSI in the frequency domain and the space domain, so that a differential mode between a product of the basis matrix and any sparse vector in the sparse vector sequence, and a column vector of a corresponding CSI channel matrix meets a predetermined condition; and synchronizing, to the BS, the determined basis matrix that comprises the sparsity of the CSI in the frequency domain and the space domain. receiving pilot information sent by the BS; determining, according to the pilot information, a CSI information matrix that comprises information about the frequency domain and the space domain of CSI; determining to-be-transmitted data by using the CSI information matrix, wherein the step of determining to-be-transmitted data by using the CSI information matrix comprises: performing compressive sensing processing on the CSI information matrix to obtain the to-be-transmitted data; and feeding back the to-be-transmitted data to the BS, so that the BS restores the corresponding CSI information from the to-be-transmitted data by using the basis matrix that is pre-synchronized with UE and comprises the sparsity of the CSI in the frequency domain and the space domain; characterized in that the method further comprises: receiving a training sequence, of a period of time, sent by the BS; measuring and calculating a corresponding CSI channel matrix sequence according to the training sequence, wherein each CSI channel matrix in the measured and calculated CSI channel matrix sequence is a matrix that comprises information about a frequency domain and a space domain of CSI; if an initialized basis matrix is given, calculating a sparse vector sequence corresponding to a sequence comprising column vectors corresponding to each CSI channel matrix; determining, according to the sparse vector sequence, the basis matrix that comprises the sparsity of the CSI in the frequency domain and the space domain, so that a differential mode between a product of the basis matrix and any sparse vector in the sparse vector sequence, and a column vector of a corresponding CSI channel matrix meets a predetermined condition; and synchronizing, to the BS, the determined basis matrix that comprises the sparsity of the CSI in the frequency domain and the space domain. receiving a training sequence, of a period of time, sent by the BS; measuring and calculating a corresponding CSI channel matrix sequence according to the training sequence, wherein each CSI channel matrix in the measured and calculated CSI channel matrix sequence is a matrix that comprises information about a frequency domain and a space domain of CSI; if an initialized basis matrix is given, calculating a sparse vector sequence corresponding to a sequence comprising column vectors corresponding to each CSI channel matrix; determining, according to the sparse vector sequence, the basis matrix that comprises the sparsity of the CSI in the frequency domain and the space domain, so that a differential mode between a product of the basis matrix and any sparse vector in the sparse vector sequence, and a column vector of a corresponding CSI channel matrix meets a predetermined condition; and synchronizing, to the BS, the determined basis matrix that comprises the sparsity of the CSI in the frequency domain and the space domain.