The authenticity of fracture distribution model is one of the key factors during numerical simulation of blasting in jointed rock mass,which would obviously affect the numerical simulation results.It is hard to represent the complex three-dimensional joint distribution in the existing joint construction method.To explore a simple and feasible operation method for constructing the complex 3D joint model in LS-DYNA software,a K file of blasting numerical model was analyzed and reorganized by MATLAB software.Furthermore,a 3D refined numerical model for jointed rock mass was constructed by the 3D joint distribution law and the constitutive joint model parameters.Finally,a statistical analysis of the three-dimensional joint distribution law was carried out in an open-pit limestone mine,and the joints were reconstructed in the numerical model of a bench blasting.Consequently,a comparative study of the numerical simulation and the field blasting test for open-pit bench blasting was carried out.The results show that the error between the joints built in the numerical model and the actual joints is less than 13%.The joint surface changes the damage distribution of the rock mass.Compared with the intact rock mass,the damage rock mass range increases by 12.04%,and the proportion of fragments with the size of 0~100 mm decreases by 8.11%.The damage results obtained by blasting simulation are close to the field rock breaking effect,and the percentage error of fragments with the size of 0~100 mm is 4.16%.The analytical reconstruction method is feasible and easy to represent the complex three-dimensional joint distribution,and the numerical results are close to experimental results.