As for one orthogonal frequency division multiplex (OFDM) signal, conventional block interleaving is implemented, but the correlation between two generated candidate signals is very strong, which degrades the improvement in peak-to-average power ratio (PAPR) reduction performance. Concerned on the limitation of conventional block interleaving, a timefrequency block interleaving scheme and its suboptimal scheme for PAPR reduction in OFDM systems were proposed. In proposed schemes, block interleaving was adopted among different OFDM signals in a timeslot, which improves the freedom of generating candidate signals and reduces the correlation between two different candidate signals. The simulation results show that, compared with conventional block interleaving, this schemes can obtain better PAPR reduction performance with the same computational complexity.