Low strain ingtegrity testing of pile is based on the one-dimensional wave theory.However, the pulse wave produced by hammer is actually 3-dimensional wave , whose propogation could be affected by the pile sides with different geological conditions. The effect is more obvious when the geological conditions of the pile sides become more complex. This test established three-dimensional finite element model which has fixed pile bottom and different geological conditions by applying ANSYS/LS-DYNA dynamic analysis method. The test simulated nine different boundary conditions of the pile sides. The results were divided into four groups to compare. And the velocity-time curve of the particle in different conditions was obtained. Through analyzing the simulation data, the conclusion that the stress wave is affected by the boundary conditions of the pile sides could be made.