Reducing the Peak to Average power Ratio (PAR) is a key to applying the technology of OFDM efficiently. In this paper, an effective method based on GCS in reducing the PAR of an OFDM signal is presented. Using this improved choice of accompany aggregate coding method, the complexity of the conventional reducing PAR method of OFDM system is reduced effectively. The better statistics of peak power in the improved transmit signal are demonstrated by the simulation results.