The perilous rock is one of the typical disasters in the Three Gorges reservoir region. Crack propagation of controlling joint under loads is the key process in failure of perilous rock. The extended finite element method (XFEM) is an effective approach for fracture analysis. The governing equation of XFEM for hydraulic fracture modeling is derived by the virtual work principle of the fracture problem considering the water pressure on crack surface. Then the implement method of XFEM for hydraulic fracture modeling is deduced. The Taibaiyan cliff at Wanzhou is a representative case of massive perilous rocks in the area. The hydraulic fracturing process on this site is simulated and analyzed by extended finite element method. The numerical analysis results show that water pressure in controlling joint of perilous rock is sensitive to the rainstorm condition. With the increases of water pressure in control joint

the tensile stress at the crack tip increases rapidly and the stability of perilous rock decreases; type I crack propagation is the main form of crack propagation in perilous rock and the crack propagation is non-steady propagation.