In order to obtain the influence of waste filling mining on surface subsidence under "three-under" coal compression environment, 1623 waste filling face of No. 6 coal seam of a coal mine was taken as the research object, a settlement observation station was set up for long-term and continuous observation, and the degree of surface subsidence was quantitatively treated by probability integral method. According to the observation data analysis of T923 gangue filling face for 40 months, the maximum subsidence of gangue filling was 83 mm, accounting for 2.07% of mining height; the advance influence distance and angle would increase slowly with the expansion of mining area and stabilize at a certain level; compared with caving mining method, the subsidence coefficient of gangue filling mining was reduced by 96% on average, and the positive tangent value of main influence angle was reduced by 52%. The maximum horizontal deformation was 0.183 m m/m and the maximum inclined deformation was 0.125 m m/m, which greatly reduced the impact of coal mining on surface subsidence and did not threaten surface structures.