Based on the systematic investigation of the engineering geological environment of the unstable slope of the Wangjiapo, firstly we determine the seismogenic fault of Ludian earthquake and its location of the slope. On this basis, we also proceed further discussion about slope structure, development characteristics and mechanism of the surface rupture in the strong deformation zone, while combining the UAV image technology. The research results shows that: The seismogenic fault of Ludian earthquake is the Baogunao-Xiaohe fault in NW, which goes through the strong deformation zone, it is play a role of control for its structure, and the surface rupture system is strictly controlled by the boundary conditions of the fault zone, and its extension is also strictly controlled by the basis geo-environment. Its belongs to small pull-apart structures, mostly belongs to the structural fracture, not slope deformation cracks. Coupling effect of the effect of earthquake and tension because the sinistral strike-slip fault move is the inducing factor of the surface rupture. Continuous rainfall can’t determine the concentration of the surface rupture, but can aggravate the development of the surface rupture.