Abstract: In order to solve the problem of top coal instability of roadway driving along goaf with fully mechanized top coal caving face，a mechanical model of top coal stability was conducted to evaluate the criterions of top coal broken and overlying strata movement law，then asymmetrical supporting idea was put forward.The results showed that top coal stability style in roadway that driving along goaf with fully mechanized top coal caving face included three types，which was almost no cracking，cracking more frequent and cracking very frequently.The position of top coal crack that located in the center of roof，which close to the coal pillar，the roadway roof near the crack point experienced the process of “collapse-rotary extrusion-collapse” ，the supporting designing of roadway roof should be an asymmetrical supporting that close to the coal pillar.Industrial test indicated that asymmetrical supporting achieved great controlling effect for roadway along goaf with fully mechanized top coal caving face.