Abstract: This research bases on CAPWAP_C method and in the light of the limitations of present PDA method to deduce fitting F and v formula of high-strain pile driving where the sensor is in 4 units. According to the deduced formula, the research braids analyzing program. Then, a fitting F and Zv figure is drawn for a certain position of sensor, and analyses the influence of PDA results by the place of sensors. Further, this paper demonstrates advantages of the new approach over the old by comparing new fitting F and Zv figure with the old one and actual one , confirms the new approach is more suitable for real engineer project.