Aimed at solving the problem that the reflected wave method does not fully make use of the information received, this paper deduces the theoretical model of pile soil system on the basis of pile vibration theory and wave theory and also imitates exciting force and property of sensor. An effective waveform fitting technique is put forward to make quantitative analysis of pile completeness. The application of this technique to engineering pile has achieved good result. In addition, this paper discusses the multi solution problem.