Abstract: An improved symbol synchronization algorithm for OFDM systems is proposed in this paper. Based on the assemble correlation method which estimates the available sampling window for FFT, the recovered binary serial is modulated for the second time. By computing the correlation of received signal and the twice modulated signal, the correct symbol timing is obtained. This data-aided method increases the SNR during the estimation. Simulation results demonstrate that the proposed algorithm has good timing synchronization performance over multi-path fading channel.