The impact-echo method is an effective method for pile integrity testing.Based on the one dimensional (1-D) stress wave theory, the range and the extent of the changes in pile impedance can be determined from the vibration curve of reflected wave at the top of pile (including travel time, amplitude and phase).However, in practice, a pile is a cylinder rather than a rod for the induced waves, and the section deformation is not uniform.In this study, the three-dimensional wave phenomena exhibited in the wave-field near the pile top are analyzed from the components of the wave excited by the point sources and the multiple reflections from the side of the pile top.The propagation behavior of the waves in the far-field, which is far from the top, is analyzed based on the longitudinal waves in cylinders.The results show that the three-dimensional wave in the near field and the dispersive characteristics of the waves in the far field can be mitigated, and the signals measured at the top can be approximately analyzed using 1-D stress wave theory when the receiver position and source frequency content meet some conditions.Under the interaction between the pile and the soil, the stress waves in the pile decay with propagation.The effects of shear wave velocities of pile and soil on the attenuation of stress wave are analyzed.It is shown that the stress wave attenuation is not only related to the shear wave velocity ratio of the pile and soil, but also related to the absolute values of the shear wave velocity of the pile and soil.The lower the shear wave velocity of the pile is, the higher the shear wave velocity of the soil is, and the faster the stress waves decay.