Abstract: Aiming at the problem of asymmetric large deformation floor heave in the 81306 No.2 return air roadway of Baode Coal Mine, and this paper introduces the butterfly-failure theory, combined with theoretical analysis and numerical simulation analysis, and studies on mechanism of butterfly-failure asymmetric floor heave in roadway along a goaf. The results show that the confining pressure ratio increases exponentially, butterfly-failure emerges in mining roadway along the goaf under the influence of mining disturbance, and the maximum principal stress is tilted to the side of the goaf, which makes butterfly blade of butterfly-shaped plastic zone rotate to the side of the roadway floor, and the rock in floor butterfly blade is badly damaged to result in a violent unsymmetrical floor heave, the floor heave is defined as the butterfly-failure asymmetric floor heave. According to the butterfly-failure asymmetric floor heave in Baode Mine, combined with numerical simulation method, it is suggested that the size of pillar along the goaf should be determined by controlling the width of coal pillar appropriately, so as to adjust the rotation angle of butterfly blade and reduce the confining pressure ratio of roadway.