Abstract: Among the total 34 parameters of RHT constitutive model, there are 19 parameters can be confirmed from experiment or theoretical study, but the left ones, N、p_comp、f_t^*、f_s^*、A、n、Q₀、g_c^*、ξ、D₁、ε_p^m、A_f、n_f、B and g_t^*, are generally hard to acquire. A sensitivity study of the 15 hard-acquired parameters was conducted through numerical simulation of uniaxial and triaxial compression of limestone using LS-DYNA. And then a new method was proposed in this paper to acquire all 34 parameters of RHT model in terms of red sandstone by orthogonal experiment coupled with static test, sonic wave test, SHPB impact test and LS-DYNA numerical simulation. The simulated result of red sandstone is in a well line with the result from SHPB impact test of red sandstone, which evidenced the RHT model of red sandstone is effective.