It is difficult to apply regular sonic echo (SE) test to existing piles for unexposed pile head conditions. Wavelet transform (WT) has good time frequency characteristics, and can greatly reduce interferences. Adopting reasonable excitation-receiver configuration, wavelet transform combining with double signal (DS) method can be used to identify the pile tip depth. The three-dimensional finite element model for soil-pile/column-beam system was used to simulate the testing. The lateral surface of the pile and top surface of the beam were struck respectively, and wavelet transform was employed to deal with the simulated signals. The effects of the excitation-receiver configuration were then investigated. It was found that, when striking in lateral surface of the pile with the inclination angle of 45o, it is better to place the receiver in the side surface of the piled column. Keeping both locations of excitation and receiver away from the superstructure is strongly recommended. As for striking the beam top surface, the receiver should be placed in the lateral surface of the pile away from the beam bottom as far as possible. Finally, the application of double signal method for wavelet waveforms is helpful to improve the precision of pile tip depth.