Abstract: The impacting characteristics of debris flow are an important basic question to study the alleviation of debris flow and topographical evolution of valley. A laboratory physical model for debris flow with 5 slurry viscosities of 0, 0.13, 0.37, 0.72 and 0.93 Pa·s, 5 solid phase ratios of 0,0.02,0.04,0.08, and 0.16, 5 grain diameters of 0, 0.075~0.2, 0.3~0.5, 0.8~1.0 cm and 1.3~1.5 cm is established. The test conditions include rinsing flow, non-viscous debris flow and viscous debris flow. The impacting loads of debris flow are denoised by means of the wavelet method. The time-history curves and characteristics of the impacting load are revealed. The results show that the mean impacting load of the rinsing flow is 2.84 kPa; the mean impacting load of the non-viscous debris flow has a direct proportion to the solid phase ratio and grain diameter, and the larger the solid phase ratio, the smaller the debris flow head, and the bigger the grain diameter, the lager the changing range of impacting load; with the increase of slurry viscosity, solid phase ratio and grain diameter of debris flow, the impacting load exhibits a nonlinear increase, and slurry viscosity has marked effects on the impacting load, and with the increase of the slurry viscosity, the mean impacting loads under the same slurry viscosity, different solid phases and grain diameters are 4.41, 5.09, 5.89, 6.46, 6.70 kPa. The results are meaningful to the study on the dynamic features of debris flow.