Embodiments of the present disclosure relate to an OFDM-based data transmission method and an apparatus. In one example method, a transmitting device generates a data packet. The data packet comprises at least one orthogonal frequency division multiplexing (OFDM) symbol. The OFDM symbol comprises N sequentially numbered subcarriers. The N subcarriers are divided into L subblocks. Each subblock of the L subblocks comprises └N/L┘ subcarriers including M pilot subcarriers. Start subcarriers of adjacent subblocks are adjacently numbered subcarriers. A numbering interval is the same for adjacent subcarriers in each subblock of the L subblocks. Each subblock of the L subblocks corresponds to one phase rotation signal. Signals carried on the subcarriers in each subblock of the L subblocks are signals obtained by multiplying original signals by a corresponding phase rotation signal. The transmitting device sends the data packet.