This application relates to the field of wireless communications technologies, and in particular, to a data processing method, apparatus, and system. This application provides a data processing method. A data sending device modulates a to-be-transmitted bit sequence, splits a real part and an imaginary part of a complex-valued symbol that is obtained through the modulation into two symbols to form a symbol sequence, performs phase rotation of symbols in the symbol sequence, and performs sending by using a single carrier frequency division multiple access (SC-FDMA) symbol. This application is intended to reduce a peak-to-average power ratio (PAPR) of a transmit signal of an orthogonal frequency division multiplexing (OFDM) system by splitting a real part and an imaginary part of a to-be-transmitted signal, and improve link quality of an entire transmission system.