An adaptive symbol synchronization algorithm is proposed in Orthogonal Frequency Division Multiplexing (OFDM) systems, which is based on pilot symbol and exploits the properties of FFT. The symbol timing and carrier phase offset is estimated jointly in frequency domain. The proposed estimator needs only simple computation and is little resource loss, which can adjust the synchronization acquisition and precision conveniently. Simulations demonstrate that the symbol synchronization is completed simply and effectively, which is very adaptive and performs at a sufficiently high level over multipath fading channels.