Abstract: in order to evaluate the suitability of the side guard plate in the hydraulic powered support of No.37220-2 fully-mechanized top coal caving mining face in a high inclined thick seam of Dongxia Mine, with th site monioring and measuring on the loading of the side guard plae the loading features of the side guard plavewere obtained.The monitoring and measuring result showed that during thefully mechanized top cal caving mining in the igh incli ne thick seam,theloading of theside guard plate in the powered support generaly would be below 20o k N and the loading of the side guard plate would be 1 .0 k N during the mine stra a weighting ,erod of the coal mining face. The monitorng and measuring analysi resuts showed that the side guard plate ofthe powered suppor in the igh inclined seam woud not oniy have a seaing function to prevent the rok waste eakage and but more important t have a function to adjust the powered support and to prevent the sliding and toplig of the powered support,Al 100 mmlarge diameter side guard ram of the powered support in Nc.3720-2 coal mining face couldbasically and ffectively pay the adjustment and guard function.