Abstract: By choosing the appropriate phase sequence, Partial Transmit Sequence（PTS） method reduces the probability of the signal peak, this method does not make the signal distortion. But conventional PTS technique has very large computational complexity, needs to traverse all the optional phase factor, its calculation sequence increases with the number of separate exponential growth. In this paper, a multi-phase sequence method is proposed, which is inverted binary tree. By symmetrical tree searching, this method searches out the optimal phase sequence. Simulation results show that the method reduces the system complexity, while the PAPR has been better suppressed.