In the conceptual framework of self-organized criticality (SOC),and by investigating the typical slopes in Ⅸ seismic zone of Wenchuan earthquake,the negative power-law relationship of landslides between volume and number,as well as between depth and number was found.Furthermore, landslides also demonstrated the similar characteristics in Ⅹ seismic zone of Wenchuan earthquake. Based on the principle of quasi-static theory,the sand-pile model centrifugation tests repeated the dynamic behavior of slope under seismic disturbances, and the dynamical characteristics of landslips can be showed with negative power distribution law when the model box floor tilted 1.5°, but showed normal distribution when 3.0°, and the cellular automaton models revealed the dynamical mechanism of the evolution of sand pile model with the changes of disturbance intensity by numerical simulation. It was suggested that the slope system in younger or maturity age has the basic properties of intrinsic SOC. There is a seismic intensity threshold, the distribution law between size and frequency of landslides triggered by earthquake can be described under the threshold, and both the huge scale and small scale landslides disasters comply with the same formation mechanism.
