An antenna port mapping method and apparatus, where the method includes performing first weighted processing and second weighted processing separately on first multichannel signal to be sent in a first polarization direction, and forming two beams in the first polarization direction after an antenna array radiates the processed first multichannel signal; and performing third weighted processing and fourth weighted processing separately on second multichannel signal to be sent in a second polarization direction, and forming two beams in the second polarization direction after the antenna array radiates the processed second multichannel signal. The method implements mapping of the antenna array to four antenna ports, thereby extending an application scenario of antenna port mapping.