Abstract: Largescale and super largescale rock landslides are not only huge in size and range,but also mostly located in mountains and valleys. Usually,site exploration can be used to determine landslide slip zone location and shape accurately. However,with extremely difficult terrain conditions and mostly at the preliminary study stage,the landslides slip surface location could not be determined accurately because of lacking of exploration data and thus strength parameters are hard to get also. This paper used the initial geological conditions for the formation of large rock landslide. They include terrain conditions,topography,lithology,structural conditions,river morphology,slope body structure and deformation damage structure,combined with slide morphological characteristics after its formation,used feedback approach and analyzed large rock landslide slip surface location and morphological characteristics. Based on the information of the location of the landslide slip surface,this paper analyzed and calculated normal stress(compressive stress)generated on the slip surface by the weight of the rock body covered the slip surface. Based on the acquired slip zone soil samples,using normal stress generated on the slip surface by landslide body weight force,this paper conducted matching laboratory tests using principle of gravity compaction to get the corresponding physical indicators on various areas. This paper also conducted matching lab tests of strength,and got strength parameters,and established the slidezone soil void ratio,water content relationship with friction coefficient and cohesion. With the relationship established from tests,combined with gravity compaction tests result of the water content at different parts,this paper analyzed and studied the slip surface strength parameters. Transfer coefficient and Morgenstern law were used to calculate the stability of landslide coefficient under natural condition,and calculated values greater than 12,which accorded with current distortion trends of landslides． Largescale rockslides，Slide surface，The principle of gravity pressure density the principle of structure regenerate and intensity regenerate，Slide surface intensity parameters