Abstract: In order to study on the goaf influence on distribution of surface subsidence，the ground surface deformation and the rock movement rule were simulated under the conditions of four different goafs form by using FLAC3D numerical analysis method.And the degree and scale of surface subsidence was analyzed for concealed goafs form.The indexes such as circularity，irregular index，equal-area circle radius in morphological methods were applicated，and the surface subsidence form was analyzed quantificationally.The research showed that，no matter whether the shape of goaf was round，surface subsidence form was round or tend to round.The greater the height of overburden strata，the smaller circularity，and the shape of surface subsidence were more tends to circle，which were consistent to the actual phenomenon of surface subsidence.Research results will provide some guidance for engineering land expropriation，geological disasters precautionary，and so on.

Key words: Surface subsidence, Goaf, FLAC3D, Circularity