Timing error sensitivity is the characteristic of orthogonal frequency division multiplexing (OFDM) system. Using superimposed training sequence, a novel weak power training sequence was proposed. The training sequence, superimposed on the cyclic prefix, has lower power than the reduplicate structure training sequence. The method can reduce the bit error rate of the system affected by the superimposed training sequence. It can make the sidelobe of the correlation lower and improve the timing synchronization accuracy by using the structural characteristic. The timing synchronization accuracy using the structure proposed at the low SNR is higher than that of the reduplicate structure. The performance of the method is checked by simulation.