Abstract: HF channel sounding using pulse compression technique requires perfect autocorrelation property of sounding sequence. Aimed at the above requirement, Zadoff-Chu sequence is applied to HF channel sounding in this paper due to its predominant periodic autocorrelation property. A sequence extension mode is designed, which makes the best use of the periodic autocorrelation property of Zadoff-Chu sequence. Simulation and experiments on the parameters such as power correlation margin, merit factor, integrated sidelobe level ratio and peak-to-average power ratio of the correlation function of Zadoff-Chu sequence, m sequence and Barker code are carried out. Discussion and analysis of the data obtained from simulations and experiments are made. The results show that Zadoff-Chu sequence has a better autocorrelation property and its four parameters related above are superior to those of m sequence and Barker code.