Abstract: A novel method called phase factor optimal pair (PFOP) is proposed to improve in genetic algorithm with partial transmitter sequence (GA-PTS). The key of PTS algorithm is to choice the phase factors. GA-PTS uses phase factors as genes to take selection, crossover and mutation. The improved method is based on the principle that the sum of several low PAPR PTS sequences has a bigger probability to obtain the OFDM signals with low PAPR. In the improved GA-PTS, the cross step is changed into the step of selecting phase factor optimal pair. The simulation results show that this improved method has 0.2dB of the PAPR lower than ordinary GA-PTS algorithm.