Partial transmit sequence (PTS) is an attractive distortless peak-to-average power ratio (PAPR) reduction technique for orthogonal frequency division multiplexing (OFDM) system. However, the complexity of PTS increases exponentially with the number of sub-blocks as it requires an exhaustive searching over all phase factor combinations. In this paper, we explored the correlation among the multiple candidate signals of PTS and proposed a modified scheme with lower complexity. The main idea is based on selecting a subset from the whole set of candidate signals by analyzing the correlation of candidate signals. Simulation results show that the performance of the modified scheme is close to the theoretical lower bound and outperforms selected mapping (SLM) scheme with the same computational complexity.