Abstract: Through field observations, we studied the coal seam state, roof structure, retained coal pillar type of 3^# coal seam in Jinxin Coal Industry after remaining coal mining. According to the state of the residual coal seam, we summarized that there are 4 kinds of roof structure types in the second mining area of Jinxin Coal Industry. With the numerical simulation software, we analyzed the roof destruction and the roof stress on the second mining working face under different roof conditions, and concluded that the breaking roof is the main factor influencing the safety production on the second mining face under the typeⅠ, Ⅱ roof conditions, while the roof caving impact force is the main factor under type Ⅲ,Ⅳ roof conditions.