The present invention provides a method and device for obtaining precoding matrix. A network apparatus comprises a plurality of groups of cross-polarized linear array antennas. The method comprises: obtaining first channel indicating information indicating a first code word; obtaining second channel indicating information indicating a second code word; determining the precoding matrix, according to the first channel indicating information and the second channel indicating information, the first code word and/or the second code word comprises phase shifts and/or amplitude differences among the plurality of groups of cross-polarized linear array antennas. Since the first code word and the second code word for determining the precoding matrix by the network apparatus comprise phase shifts and amplitude differences among cross-polarized linear array antennas, the phase shifts and amplitude differences among cross-polarized linear array antennas are considered when the network apparatus sends downlink data according to the precoding matrix, so as to be able to improve the receiving quality of the sent data, thereby improving the system performance effectively.