Methods for determining the depth of a pile tip with parallel seismic testing（PST） have not be demonstrated with both theory and experiment.An axisymmetric finite element model was herein deve-loped to simulate the time-versus-depth patterns of the first arrival P wave in PST for an intact pile impacted on its top.The results show that the time-versus-depth plot of P wave consists of three parts: an upper straight section

a curved section and a lower straight section.The lower straight section should be fitted with data at depth greater than 5 times of the pile-borehole spacing under the pile tip.It was proved that the formulation of time-versus-depth in the PST with the simplified ray theory proposed by the second author of this paper and Zhao could agree well with the finite element analysis and then could give a reasonable depth for the involved pile tip

which is worth of application after further verification by field tests.