[Objective] To provide scientific support for the disaster prevention and reconstruction of debris flow dams, an experimental study on the process of debris flow dam break under different factors was conducted.[Methods] Dam failure tests were carried out under different inflows, dam shapes, clay contents, dam heights, and initial water contents. The breaking process was divided into four stages:slope surface erosion process, scarp erosion process, lateral erosion process, and decline. The failure mechanism of the debris flow dam was analyzed, and the formula for calculating the critical opening condition for the downstream slope sediment was obtained.[Results] There was a nonlinear positive correlation between the outburst discharge and the inflow water flow. The peak discharge of the outburst increased with the slope degree of the backwater slope. The outburst peak discharge increased rapidly with the increase in the height of the dam, and there was a negative correlation between the clay content and the outburst flow. The peak discharge of the outburst flow decreased slowly with the increase in the initial water content of the soil, but the range of variation was not large.[Conclusion] Among the different factors of debris flow dam break, dam height and clay content have the greatest influence, followed by incoming water flow, backwater slope and initial water content have the least influence.