Abstract: According to the understanding of the hydraulic powered support jammed mechanism in coal mining in seam with a shallow mining depth,the paper analy zed the cause of the hydraulic powered support jammed accident occurred when the hydraulic powered support had a working resistance of 12 000 kN in No.22103 fully mechanized coal mining face of Daliuta Mine.The relative prevention and control measures were provided.The results showed that an over boundary mining in the up se am of a nearby small mine made the No.22103 coal mining face had a mining of the overlying left coal pillars during the coal mining process.During the process,the rela tive rotary movement of the three hinged key block structure above the coal pillar caused the load on the key layer structure between the two seams too higher and lost stability.Thus the powered supports in the coal mining face jammed.According to the conditions,the distribution conditions of the overlying coal pillar should be verified f irst and then the powered support jammed accident could be prevented with the reduction of the rotary space of the key block above the coal pillar,the reduction of the coal mining height,the improvement of the support quality and others.