In order to analyze characteristics of overlying strata activities after top coal caving in 13102 working face, UDEC numerical simulation method was used to study this in?overhead mining. The result showed that with fully mechanized working face advancing, the working face was directly on the rise, and the basic roof would constantly break and collapse, but basic top rotary volume was large, and roof breaking failed to form "masonry beam structure, which caused strata behaviors of fully mechanized caving face was more severe and then working resistance of fully mechanized caving face of hydraulic support appeared greater value, especially for the tail of hydraulic support.