According to the roadway deformation of Jianxin Mine of Jiangxi Fengcheng Mining Bureau. Based on the basic theory of elastic-plastic mechanics, the Mechanical principle of soft rock roadway deformation was analyzed; the calculating formula of surrounding rock and plastic zone radius and the radius of rupture zone were gained. Then the numerical simulations of the soft rock roadway deformation were conducted by ANSYS software. The roadway deformation graph and the strain and stress nephogram were gained. The simulation results are agree with the measured deformation of the roadway.