Abstract: In order to mining steep incline difficulty mining thick coal seam safety and effectively under extra complicated geological situation，it taking No.4 coal seam of Jiangyuan coal industry as experimental object，and then the following parameters were analyzed, such as mining working face layout，mining technique，top coal cavability，equipment selection and matching，top coal and harden roof weaken and so on，and then the main parameters and key technique of oblique segmentation section and short wall fully mechanized top coal caving were put forward, which include “ single drum shearer and light-duty caving support”，ends integrated feed way and top coal seam and harden roof weaken and so on.After successfully application in field，it references for steep incline and thick seam fully mechanized top coal caving of No.1，No.6 coal seam and similar situation.