The abandoned loess cave slope of Sipo Village, Chang'an District in southwest of Bailu Plateau was taken as the research object in this paper. And the characteristics of stress and strain of the cave slopes under different cave states were simulated with the help of MADIS GTS NX finite element software, thus further revealing the deformation and failure mechanism of the abandoned loess cave slope and put forward corresponding prevention measures. The analysis and summary of the MADIS numerical simulation results of the cave slopes in different states shows: as the cave is abandoned, the increase of the soil moisture content leads to the decrease of the mechanical properties of the soil and the loss of the local free surface soil. Furthermore, with the effect of rainfall, the mechanical properties of the soil are further reduced, and the arch structure of the cave is destroyed, which causes the collapse of the slope where the cave is located and other overall failure.