Abstract:By the industrial mining experiments and observed data of working faces No.51101(240 m in length) and No.51104(300 m in length) in Shangwan coal mine of Shenfu—Dongsheng mining district,the effects of increasing face¢s length on underground pressure¢s behaviors were explored,and the conclusions are drawn as follows:(1) weighting span becomes shorter;(2) cycle weighting strength is relaxed;(3) the rock pressure distribution is shown that the quadric parabola relations can be used for the working face¢s middle point as symmetrical axis(i.e. coordinate origin);(4) the regression relation between maximum resistances and initial ones is liner;and (5) the support¢s loads in non-weighting period and underground pressure behavior with increasing face¢s length are enhanced,and roof weighting impact load was larger than the support¢s maximum resistance for large mining height and supper-long faces.