Abstract: Take the +590 m shaft station of Shanghaimiao Mining Area as the research object, the dynamic grouting numerical simulation method is constructed by using the strain softening constitutive model and FISH language built in FLAC^3D numerical simulation software. The method can automatically determine the grouting range according to the size of the plastic shear strain of the surrounding rock, and improve the cohesion value of the coal rock mass in the grouting range according to the section function. Through the comparison of the surrounding rock deformation after different grouting time（deformation of surrounding rock after primary support）, the theoretical value of reasonable grouting time was obtained, then the field measured deformation was compared with the simulated value, and the rational grouting time was obtained. According to the grouting range of numerical simulation, the designed length for roof and roadside grouting anchor cable is given. The above analysis results are applied to the secondary reinforcement of soft rock roadway in the field, and the test results show that the test results are good, which verifies the scientificity and feasibility of dynamic grouting simulation method in this paper.