Abstract: SLM (selected mapping) is an effective algorithm to reduce peak-to-average power ratio (PAPR) of OFDM (orthogonal frequency division multiplexing) signal without distortion. But the conventional SLM technique has the disadvantage of the loss of data transmission rate due to the bandside information on phase sequence. An improved SLM technique is therefore put forward to reduce PAPR of OFDM system by way of embedding the information on phase sequence in the check symbols of OFDM data block, so as to avoid the loss of data transmission rate due to intentional bandside information transmission. Matlab simulation results showed that the improved SLM technique is better than the conventional one in reducing PAPR since no undue system complexity will happen.