Using the self_developed model flume structure,The PFC2D numerical simulation soft was used,When the gradien was twenty five degree the happening process of debris flow was used to test and simulate under fixed flow per unit width,the result indicated that：slope toe happened firstly headward erosion,the initiation process of debris flow exist a time which the temporary relative quiet and own rising phenomena,the damage form as a whole was collapse damage from up to down,it can be better simulate the whole happening process which include the initiation、moving、accumulation of debris flow by using PFC2D numerical simulation,the study results can provide guidance meaning for the later numerical simulation and practical engineering.