This application provides a data transmission method and an apparatus. The method includes: obtaining, by user equipment, to-be-sent user data; performing, by the user equipment, channel encoding on the to-be-sent user data to obtain N sets of encoded data; performing, by the user equipment, codebook mapping on each of the N sets of encoded data by using a codebook, to obtain N sets of codebook-mapped data, where different sets of encoded data use codebooks that occupy mutually different non-zero physical REs, the non-zero physical RE means a non-zero waveform obtained after mapped data is mapped to a physical RE, and N is a positive integer greater than or equal to 2; and sending, by the user equipment, the N sets of codebook-mapped data to a base station.