Abstract: Aimed at the limitation of the traditional method for determining protection region,combined with the actual situation of Wangxingzhuang Coal Mine,similarity simulation is carried out for the protevtive layer situation, expansion deformation and stress variation of overlying strata about protected layer during mining are analyzed.The relief angle along trend direction is got according to the overburden stress changes.The results show that the determinated trend protection region is in accord with the actual site situation, it has a certain guiding significance for safe production of coal mine.