This application provides a data transmission method, so that data transmission reliability can be improved. The method includes: receiving, by the terminal device, a plurality of reference signals used for channel measurement; and sending, by the terminal device, a plurality of pieces of first indication information based on the at least one reference signal and a transmission scheme on which CSI feedback is based, where the plurality of pieces of first indication information are used to indicate x target precoding matrices, at least one of the plurality of pieces of first indication information is used to indicate one target precoding matrix, and the x target precoding matrices are determined based on the plurality of precoding matrices, where x is a quantity of target precoding matrices that need to be fed back, and x is an integer greater than 1.