Abstract: The coal mining with fly ash paste filling is the most effective mining technology under buildings and also an important part of the green mining at present. In this paper, numerical simulation and prediction were carried out on the surface subsidence control in coal mining with the fly ash paste filling by taking the coal mining under buildings in a certain mining area as an example, 3 layers were all mined by slicing and filling, with the maximum vumulative subsidence amount of 125 mm, the maximum inclination deformation amount of 0.39 mm/m, the maximum curvature deformation of 0.003×10^-3 m^-1, the maximum horizontal displacement of 56 mm and the maximum horizontal deformation of 0.3 mm/m, the inclination deformation, horizontal deformation and curvature deformation were all within the allowable range of grade Ⅰ damage deformation. The prediction results showed that the coal mining technology under buildings with fly ash paste filling was technically feasible and can provide the technical basis for the coal mining under buildings.