A multi-antenna channel measurement method, comprising: sending (S1, S3), a first channel state information-reference signal, CSI-RS and a second CSI-RS to a terminal, wherein the first CSI-RS and the second CSI-RS are separately sent by using antenna elements in orthogonal dimensions; receiving (S2, S4), a first CSI measurement result for the first CSI-RS and the second CSI-RS and that is fed back by the terminal; sending, a third CSI-RS to the terminal according to the first CSI measurement result, wherein the third CSI-RS has been precoded according to the first CSI measurement result; and receiving, a third CSI measurement result that is for the third CSI-RS and that is fed back by the terminal; wherein the first CSI measurement result comprises a first precoding matrix indicator, PMI, that is corresponding to a first codebook; wherein the first codebook is a diagonal matrix, W 1, comprising two sub-matrices, and the two sub-matrices are respectively corresponding to the two polarization directions of antenna elements; and each column of each sub-matrix is a column selected from a matrix X, the column of each sub-matrix selected from the matrix X forms a wide beam in a same polarization direction of the antenna elements, an element in an i th row and a j th column of the matrix X is X i, j ̅ = e j 2 π i − 1 j − 1 K, i ∈{1,2,..., I], j ∈{1,2,..., K}, wherein if the first CSI measurement result is fed back for the first CSI-RS, I is a half of a quantity of ports for the first CSI-RS, or if the first CSI measurement result is fed back for the second CSI-RS, I is a half of a quantity of ports for the second CSI-RS, and K is a quantity of narrow beams supported by a system; or wherein the first codebook is a matrix that is corresponding to a same polarization direction of the antenna elements, each column of the matrix is a column selected from a matrix X, the column of each sub-matrix selected from the matrix X forms a wide beam in a same polarization direction of the antenna elements, an element in an i th row and a j th column of the matrix X is X i, j ̅ = e j 2 π i − 1 j − 1 K, i ∈{1,2,...,I}, j ∈ {1,2,..., K}, wherein if the first CSI measurement result is fed back for the first CSI-RS, I is a quantity of ports for the first CSI-RS, or if the first CSI measurement result is fed back for the second CSI-RS, I is a quantity of ports for the second CSI-RS, and K is a quantity of narrow beams supported by a system. sending (S1, S3), a first channel state information-reference signal, CSI-RS and a second CSI-RS to a terminal, wherein the first CSI-RS and the second CSI-RS are separately sent by using antenna elements in orthogonal dimensions; receiving (S2, S4), a first CSI measurement result for the first CSI-RS and the second CSI-RS and that is fed back by the terminal; sending, a third CSI-RS to the terminal according to the first CSI measurement result, wherein the third CSI-RS has been precoded according to the first CSI measurement result; and receiving, a third CSI measurement result that is for the third CSI-RS and that is fed back by the terminal; wherein the first CSI measurement result comprises a first precoding matrix indicator, PMI, that is corresponding to a first codebook; wherein the first codebook is a diagonal matrix, W 1, comprising two sub-matrices, and the two sub-matrices are respectively corresponding to the two polarization directions of antenna elements; and each column of each sub-matrix is a column selected from a matrix X, the column of each sub-matrix selected from the matrix X forms a wide beam in a same polarization direction of the antenna elements, an element in an i th row and a j th column of the matrix X is X i, j ̅ = e j 2 π i − 1 j − 1 K, i ∈{1,2,..., I], j ∈{1,2,..., K}, wherein if the first CSI measurement result is fed back for the first CSI-RS, I is a half of a quantity of ports for the first CSI-RS, or if the first CSI measurement result is fed back for the second CSI-RS, I is a half of a quantity of ports for the second CSI-RS, and K is a quantity of narrow beams supported by a system; or wherein the first codebook is a matrix that is corresponding to a same polarization direction of the antenna elements, each column of the matrix is a column selected from a matrix X, the column of each sub-matrix selected from the matrix X forms a wide beam in a same polarization direction of the antenna elements, an element in an i th row and a j th column of the matrix X is X i, j ̅ = e j 2 π i − 1 j − 1 K, i ∈{1,2,...,I}, j ∈ {1,2,..., K}, wherein if the first CSI measurement result is fed back for the first CSI-RS, I is a quantity of ports for the first CSI-RS, or if the first CSI measurement result is fed back for the second CSI-RS, I is a quantity of ports for the second CSI-RS, and K is a quantity of narrow beams supported by a system.