Taking the old goaf of Xiaoma Mine, Jiaozuo Coal Group Corporation as an example, this paper combines on-site research with theoretical analysis to analyze the activation factors of the old goaf. There are two factors that cause the activation of the old goaf. One is that the old goaf collapse torn belt produces activation, the other is the surface movement and deformation under load. This paper uses the numerical simulation to study the ground movement caused by the housing load deformation of foundation stability, and obtain three foundation maximum load capacities in different areas. Then, it gives some proposals about the corresponding area height of the floor construction. Finally, it analyzes the foundation treatment measures goaf, and the overall suitability for building goaf, providing references for the actual construction projects.