Abstract: In order to study the influence of the gap height on the vibration intensity of the shaft wall, a wellbore blasting model is established by finite element method, and the vibration signals are acquired from above model. The validity of the model itself and the parameters used in the model are tested by the on-site monitoring data. The wavelet packet analysis method is used to analyze the frequency spectrum of the monitoring signals; so as to facilitate to compare the energy of each sub-band of different monitoring points, an energy normalization factor is proposed. The results show that: the gap height is an important factor affecting the vibration strength of the shaft wall, there is the most unfavorable air gap height. The most unfavorable gap height is 2.7 m, and the optimal gap height is 3.6 m in this project, the peak vibration energy is reduced by 20% under the same blasting scheme. The attenuation laws of the sub-bands are inconsistent, and the attenuation laws at the top and bottom ends are also different, the energy in the vicinity of the diffraction ends is highly oscillatory. The wall of the bottom mold is in the local oscillatory region of blasting seismic wave diffraction, the correlation between the blasting vibration intensity and the core distance is not established, and the vibration intensity at the top and bottom ends is not fixed.