Abstract: The movement law and impact performance of debris flows have decisive significance to the influence range and severity of debris flow disasters. This paper uses the discrete element simulation software EDEM 2018 and conducts a numerical simulation study on the debris flow flume test, taking into account the influence of the flume slope, barrier angle and particle size distribution. Based on the existing research results, the solid particle movement process and its impact performance have been systematically studied. The numerical simulation results are compared with the existing flume test data to verify the reliability of the numerical simulation method. On this basis, the following conclusions are drawn:(1)When the barrier angle and particle size distribution remain constant, the larger the flume slope, the greater the corresponding peak velocity and impact force; (2)For the model with the same flume slope and particle size distribution, the steeper the barrier, the more particles interact with it, and the faster the flow reaches the peak of velocity and impact force, and the corresponding peak of velocity and impact force is also greater.; (3)During the movement of debris flow, the debris flow of each particle gradation exhibit reverse order characteristics. And the fine particles are distributed in the lower part and the rear part of the sliding body, which improves the sliding speed of the sliding body and reduces the impact force. While the coarse particles have little effect on the moving speed and would increase the impact pressure on the barrier structure.