An antenna port mapping method, used to implement mapping of an antenna array to four antenna ports, wherein the antenna array comprises multiple columns of antenna elements and has a first polarization direction and a second polarization direction, and the method comprises: Performing first weighted processing and second weighted processing separately on first multichannel signal to be sent in the first polarization direction, and forming a first beam and a second beam in the first polarization direction after the antenna array radiates the processed first multichannel signal, so as to implement mapping of the antenna array to two ports in the first polarization direction; and performing third weighted processing and fourth weighted processing separately on second multichannel signal to be sent in the second polarization direction, and forming a third beam and a fourth beam in the second polarization direction after the antenna array radiates the processed second multichannel signal, so as to implement mapping of the antenna array to the other two ports in the second polarization direction, characterized in that a weighted value for the second weighted processing is a reverse conjugation of a weighted value for the first weighted processing and a weighted value for the fourth weighted processing is a reverse conjugation of a weighted value for the third weighted processing, wherein the first weighted processing and the second weighted processing are implemented by using a first weighted value matrix, and the first weighted value matrix is: α 1, α 2, ⋯, α s α s, α s − 1, ⋯, α 1, wherein s is a quantity of columns of the antenna array; and the third weighted processing and the fourth weighted processing are implemented by using a second weighted value matrix, and the second weighted value matrix is: β 1, β 2, ⋯, β s β s, β s − 1, ⋯, β 1, wherein s is the quantity of columns of the antenna array. Performing first weighted processing and second weighted processing separately on first multichannel signal to be sent in the first polarization direction, and forming a first beam and a second beam in the first polarization direction after the antenna array radiates the processed first multichannel signal, so as to implement mapping of the antenna array to two ports in the first polarization direction; and performing third weighted processing and fourth weighted processing separately on second multichannel signal to be sent in the second polarization direction, and forming a third beam and a fourth beam in the second polarization direction after the antenna array radiates the processed second multichannel signal, so as to implement mapping of the antenna array to the other two ports in the second polarization direction, characterized in that a weighted value for the second weighted processing is a reverse conjugation of a weighted value for the first weighted processing and a weighted value for the fourth weighted processing is a reverse conjugation of a weighted value for the third weighted processing, wherein the first weighted processing and the second weighted processing are implemented by using a first weighted value matrix, and the first weighted value matrix is: α 1, α 2, ⋯, α s α s, α s − 1, ⋯, α 1, wherein s is a quantity of columns of the antenna array; and the third weighted processing and the fourth weighted processing are implemented by using a second weighted value matrix, and the second weighted value matrix is: β 1, β 2, ⋯, β s β s, β s − 1, ⋯, β 1, wherein s is the quantity of columns of the antenna array. α 1, α 2, ⋯, α s α s, α s − 1, ⋯, α 1, wherein s is a quantity of columns of the antenna array; and the third weighted processing and the fourth weighted processing are implemented by using a second weighted value matrix, and the second weighted value matrix is: β 1, β 2, ⋯, β s β s, β s − 1, ⋯, β 1, wherein s is the quantity of columns of the antenna array.