Abstract: Due to its special modulating characteristics, the orthogonal frequency division multiplexing (OFDM) technique results in a high peak-to-average power ratio (PAPR). The high PAPR signal to power amplifier needs strict linearity, and it thus becomes the main obstacle for OFDM technique to be applied in practice. An improved SLM selected mapping method is therefore put forward to reduce PAPR of OFDM system. The phase sequence is required to be embedded in the check operators of the OFDM data block so as to avoid the data transmission rate loss and reduce PAPR more efficiently by clipping. A computer simulation was done with the improved method and the results proved that it can reduce the PAPR of OFDM system more than conventional SLM technique with no code errors increased.