Slope debris flow is a natural hazard constantly observed in the mountain area. Taking the Beibei of Chongqing City as an example,the paper analyzes the self-organization criticality of solid loose materials,and the criticality of geomorphology and rainfall while slope debris flow occurs.From viewpoint of self-organization(criticality),non-linear interaction exists between different subsystems in the formation of slope debris flow,and causes the system to develop naturally to a state of self-organization criticality.Under triggering by storm,slope debris flow occurs eventually.There exists a power correlation between its magnitude and frequency,which is a behavioral sign of debris flow as self-organization.In addition,occurrence law of slope debris flow can be predicted and forecasted through the power correlation.