Based on instability of large inclination support of 1622 fully mechanized caving mining face in Gequan Mine, mechanical analysis was made for instability of support in field practice and several technical measures about how to improve stent stability were put forward, which had outstanding effect on 1622 fully mechanized caving mining face. It not only solved problems of unstable suppport but guaranteed stable and high yield in fully mechanized top coal caving mining face.