Abstract: The iron mine excavated is easy to form ground subsidence and collapse disaster,how to accurately determine the gob influence sphere in iron mine become an important issue.The paper introduced the analytical method,as well as the calculation assumptions,formula and its parameter optimization.In the meanwhile,this paper,using the actual projects as sample,conducted the iron mine gob influence sphere calculation by analytical method and numerical simulation,compared the differences of two methods,analyzed the causes of differences,and provides some references for gob influence sphere evaluation calculations.