Abstract: Aiming at the serious rib spalling situation at 3305 soft seam large mining height face in Zhaozhuang Coal Mine, by using FLAC^3D numerical analysis software and Coulomb-Mohr yield criterion theoretical calculation method, the width of plastic zone of soft seam large mining height of Zhaozhang Mine was simulated and calculated. Through the analysis, it was obtained that the mechanism and the main influencing factors of the soft seam rid spalling in large mining height face and the prevention measures for rib spalling were proposed.