Abstract: In terms of the supports failure problem when the working face No. 206 advanced the bottom of the connection roadway retained in overlying barrier pillar between panels in the 12down coal seam in Huojitu colliery of Daliuta coal mine in Shendong mining area, theoretical analysis and similar simulation were applied in this manuscript to study the mechanism of supports failure in the head of fully mechanized caving face in lower slice. The research result indicated that the main roof was broken in the shape of ‘vertical O-X’ after the higher slice mined and the stable hinged structure of arc triangular block was formed in the side of mining roadway. While when the fully mechanized caving face in lower slice advanced the bottom of the connection roadway retained in overlying barrier pillar between panels, the existences of connection roadway and surrounding rock mass plastic zone made the effective bearing area of arc triangular block supported by coal body declined dramatically. Under the impact of overlying load, the stable hinged voussior beam structure of arc triangular block became cantilever beam structure after sliding instability, and meanwhile the overlying load inflicted on supports in the head of the working face No. 206 of the 12 upper coal seam therewith increased, which caused supports failure accident. This is the primary reason for the occurrence of supports failure when the lower slice advanced the bottom of the connection roadway retained in overlying barrier pillar between panels. Based on this, some measures, like intensifying the supporting intensity and increasing the density and strength of seine in the head, optimizing the layout of roadways were proposed to guarantee the production security. The research result can provide reference to the high yield and high efficiency productivity under the similar mining conditions in shallow coal seams.