Abstract: Owing to the large amount of computation, the finite-difference method in time-domain is rarely applied to simulating underwater acoustic propagation in a Cartesian coordinate system. In this paper, the finite-difference timedomain method is used to derive an approximate expression of acoustic wave equation in a cylindrical coordinate system, and then by combining it with complex frequency shifted perfectly matched layers, a shallow water acoustic propagation model is constructed. The model reduces the amount of calculation and can accurately predicts the propagating signal waveforms and evolution process of the acoustic propagating fields in time domain and the transmission loss curves in frequency domain. Acoustic fields of Pekeris waveguide in shallow water are simulated by the finite-difference time-domain model in a cylindrical coordinate system. The scope of application of the model is analyzed by comparing normal mode model and wavenumber integration model. Results show that the proposed finitedifference time-domain method is highly accurate for short-range and medium range acoustic field prediction in shallow water. The stability of the model depends on the discrete spatial and time grid steps. For higher frequency of source, the space and time grid steps need to be smaller, which increase the amount of calculation. The accumulation of dispersion error of the model yields inaccurate acoustic field at long range. The research results show that the finitedifference time-domain model is more applicable to predict low-frequency short-range and medium range propagation field in shallow water.