Applied research on the serial multi-point vibration acquisition testing method was conducted to overcome the limitations of the traditional low-strain reflected wave method in detecting the integrity and pile length of piles under bearing slabs. Aiming at the energy dissipation phenomenon of traveling waves during their propagation in piles, the existing serial multi-point vibration acquisition testing theory was revised. The serial multi-point vibration acquisition testing signal reconstruction theory considering traveling wave attenuation was proposed by incorporating the energy dissipation of traveling waves propagating between adjacent sensors. On this basis, the applicability and effectiveness of this method were verified through numerical analysis and field tests. Meanwhile, the influence of key technical indexes such as pile body information, sensor arrangement and excitation mode on the reconstructed velocity response curves was analyzed. The results demonstrated that decomposing the original signals collected by adjacent sensors to separate downward and upward traveling waves, and then defining a generalized frequency response function by dividing the upward traveling waves by the downward traveling waves in the frequency domain, could effectively eliminate the interference from complex vibrations of the superstructure while fully retaining all characteristic information of the pile below the intermediate sensor. The testing method proposed in this study could clearly identify the reflected signals from the pile bottom and defects, and the estimated pile length was almost consistent with the actual pile length, which proved that it could be effectively applied to the integrity detection of piles under bearing slabs.