Aimed at the problems that timing synchronization algorithm is sensitive to frequency offset caused by multipath fading and Doppler spread in aviation communication, and is relatively poor in performance under condition of low signal-to-noise ratio, a synchronization algorithm is proposed by using constant envelope zero autocorrelation (CAZAC). A leading sequence with conjugate symmetry features is designed by using CAZAC sequences, and based on the structural features of the leading sequence, the cross-correlation is utilized for designing a timing metric function for accumulating peaks. The correlation value at the correct timing position is used to estimate the decimal frequency offset, and lastly, a pair of identical CAZAC sequences is used to complete the second decimal frequency offset estimation. The simulation results show that when the correct detection probability reaches 100%, the performance of the improved algorithm improves by 3 dB.