The present disclosure discloses a data transmission method, a transmit end device, and a receive end device. The method includes performing bit mapping processing on a first part of bits of a first data bit group, to generate a first modulation symbol and determining a first precoding matrix from multiple preset precoding matrices according to a second part of bits of the first data bit group. The method also includes performing precoding processing on the first modulation symbol according to the first precoding matrix, to obtain a first modulation symbol matrix and transmitting the first modulation symbol matrix to a receive end device by using at least two antennas.