In view of the unclear change of runoff particle output law caused by permeable brick blockage, the influence of permeable brick blockage on the surface runoff particle scouring law was studied by means of model simulation and factor analysis. The results show that the blocking degree and rainfall return period are important factors affecting the particle scouring process of runoff on the surface of permeable brick. The higher the blocking degree and rainfall return period, the stronger the initial scouring effect and the greater the cumulative scouring amount of particles. Combined with the runoff particle scouring process of permeable bricks with different blocking degrees under different rainfall return periods, the dynamic variation of blocking degree is introduced to modify the traditional exponential scouring model, and the runoff particle scouring model suitable for permeable brick with different blocking degrees is established. The blocking degree of permeable brick can significantly affect the particle size distribution in runoff, and has an interactive effect with rainfall return period and runoff duration.