Abstract: Taking the large inclination coal seam with dip mining stope as the research object of 2317 working face of Geting mine ,by using the method of similar material simulation and theoretical analysis,the movement laws of roof ,the tabscission layer of the overlying strata,immediate roof damage rules and dynamic evolution rules of basic roof structure were studied.The results show that the roof weighting interval is longer when adopt dip mining,which the first weighting interval of basic roof is 50m and the periodic weighting interval is 25m;stope abscission layer as "a acute triangle shape" formed composite structure moves regularly from under a rock; immediate roof is Irregular caving then the caving rock are sliding to face,which is bad for working face and basic roof can become immediate roof when working face is advancing to a certain distance to make position of immediate roof up, basic roof structure obvious movement areas mainly in the inclined upper part,basic roof structure in the vertical strata of breakage and movement is steady,basic rock beams develop to the upper strata along the tendency as a "step".

Key words: large dip angle of coal seam, dip mining, strata abscission layer, caving form, basic roof structure