Abstract: According to one pass mining with high thick seam in the fully-mechanized top coal caving mining face in ultra thick seam,the support pressure influence sc ope obvious increased problem,on the premise to ensure a long term stability of the seam gateway,a rational terminal mining coal pillar( protective coal pillar of the seam g ateway) width was determined. Based on No.8106 fully-mechanized top coal caving mining face in the ultra thick seam of Tashan Mine as a study object,a continued monit oring and measuring was conducted on the coal pillar stress between the designed mining terminal line and the gateway of No. 8106 fully-mechanized top coal caving mini ng face. A completed variation curve of the coal stress with the forward advancing distance and time was obtained. The results showed that after the mining operation of th e coal mining face stopped,the support pressure of the fully-mechanized top coal caving mining face in the ultra thick seam would still be varied slowly and would be in sta bilization after 70 days. The advance support pressure influence scope of the coal mining face was about 70 ~ 80 m and a general influence scope would be less than 110 n.