In this paper, we present a Non-data-aided (NDA) timing algorithm for phase-shift keying modulation. The absolute value operation is used to eliminate the efiect of the symbol information on symbol timing. The theoretical analysis shows that the proposed estimator is an unbiased estimation, and the upper bound of the estimated variance is close to the Modifled Cramer-rao Bound (MCRB). The simulation results also verify the conclusion of the theoretical analysis.