Abstract: In the engineering of rock breaking by the impact hammer or blasting,in order to optimize the design and construction scheme,it is often necessary to grasp the mechanical characteristics of rocks under dynamic loads. RHT model can be used to simulate the damage characteristics of brittle materials such as granite. The accurate determination of the granite RHT model parameter requires many numerical simulations on the basis of dynamic tests under different strain rates,and then the parameters of RHT model are optimized. The numerical simulation process is complicated and the efficiency is very low,which brings great inconvenience to engineering personnel to determine the parameters of RHT model. In this paper,a method for determining parameters of granite RHT model based on MATLAB is proposed. The input file,execution file and result file of LS-DYNA software are modified and processed by MATLAB software,and then the joint numerical simulation of MATLAB software and LS-DYNA software is realized. The parameters of granite RHT model in Shenzhen Zhongshan Tunnel are optimized. The method can provide an effective way to determine the parameters of RHT model in practical projects.