The shock signal’s fluctuation characteristics of debris flow stem from two aspects, one is the composition of debris flow with the solid and the liquid, another is the surging property of debris flow in motion. Based on the initial shock signals collected in model experiment in laboratory, 9 shock spectrum levels are decomposed by the db8 wavelet method, i.e., 0~0.195Hz, 0.195~ 0.391Hz, 0.391~0.781Hz, 0.781~1.5625Hz, 1.563~3.125Hz, 3.125~ 6.25Hz, 6.25~12.5 Hz, 12.5~25Hz, and 25~50Hz. Taking the peak each shock spectrum as the standard, the energy distribution curves of 9 shock spectrum levels are obtained. These curves display that the shock energy of debris flow focus on the low frequency smaller than 1.0Hz, and the percentage below 6.25Hz is about 95%. The results provide a reference to select wallop peak as the design load of structures against debris flow disaster.