Abstract: In order to solve the problem of supersedure tension of working face and low mining rate in Hexi Coal Mine, we propose technique of filling paste without coal pillar beside mine roadway at 3303 face. Through the establishment of mechanics structure model along goaf roadway, we carried out theoretical analysis for migration laws of the roof, and derived filling body support resistance formula in thick coal seam. Using FLAC numerical simulation, taking the vertical stress distribution of surrounding rock as measurement index, we optimized filling body width and intensity values. Reasonably selecting the paste material, we carried out experimental study of the strength properties and pumpability, and determined the best proportion of the filling material. Field application shows that the filling technology is feasible, and the filling effect is good.