Among the secondary mountain disasters triggered by the ＂5·12＂ Wenchuan great earthquake,most were collapses of rock and soil slope.Based on the field investigation along State Road G213 from Dujiangyan to Yingxiu and its Shuimo branch road,the collapse disaster mode,failure mechanism and self-organized criticality（SOC） dynamical characteristics of rock and soil slope are analyzed and summarized in detail.The investigation area covers Ⅸ,Ⅹ,Ⅺ seismic intensity zones,and collapse site numbers are 105.By statistical analyzing the volume and depth of the collapses,it is found that in Ⅸ zone volumes and depths of collapses obey negative power law distribution,display self-organized criticality（SOC） dynamical characteristics,but in Ⅹ,Ⅺ zones the collapse dynamical characteristics does not show self-organized criticality,it is controlled by earthquake intensity.