Abstarct: The movement of unstable, compacted and non-compacted sedimentary laxyers on the slope (landslide) has different types. Debris flow is a kind of landslide type that can happen very slowly or very fast and have disastrous effect. Mudflow is a kind of debris flow that falls into the classification of Non-Newtonian fluid. In this research, firstly, having considered the Herschel–Bulkley`s behavioral model and the smoothed-particle hydrodynamics method we focus on modeling of gush of mudflow due to removal of the valve. The gained data of this modeling are compared with laboratory tests results. The results indicate that both experimental and modeled mudflow have similar and acceptable results. Afterwards, the effect of the type and curvature of surfaces have been studied. For this purpose, two samples of the slope with curved and concave curvatures were compared with their equivalent slopes. The results show that the displacement and velocity of the material in the concave slope, are greater than these parameters in the respective slope. also in the convex slope, the amount of displacement and velocity is less than the corresponding slope. so, the use of the equivalent slope is not always trustable for flow modeling. Hence a mountain with real topography was modeled and transmitted to the software. Comparing the results of this topography modeling with its corresponding slope modeling shows that when the slope of the mountain is convex, the flow velocity in the mountain is lower than the corresponding slope, but in the hillside with concave slope the flow velocity is more than this parameter in equivalent slope. Finally, it can be concluded that the use of the topography of each region to predict the run-out distance of the mudflow can give more accurate results instead of equivalent slope, and Abaqus software has a good ability to perform such simulations.