Abstract: Time and frequency synchronization is one of the key technologies of OFDM systems. In order to achieve desirable synchronization performance under complicated multipath fading channels with jamming, we propose a new antijamming OFDM synchronization method, for which the training sequence is composed of two repetitive Constant Amplitude Zero Auto Correlation (CAZAC) sequences within one OFDM symbol. For this proposed method, the training sequence is generated in frequency domain, and windowing is perfomed in time domain to reduce the influence of jamming.The relative threshold and several correlation peaks are jointly used to improve the performance of timing synchronization. Meanwhile, the carrier frequency offset is estimated based on the correlation value to reduce the influence of jamming on the frequency synchronization. Simulation results show that this proposed novel method can improve the synchronization accuracy and the antijaming capability. Therefore, it can work well in complicated multipath channel environments with jamming.