Stress-strain curves of a RDX Based cast PBX were obtained using an INSTRON testing machine and an optimized Split Hopkinson pressure bar(SHPB) at different strain rates(10^-4~10^-2/s and 843²~1490⁴/s). Results show that mechanical properties of the material including elastic modulus, compressive strength, and strain at-maximum-stress, increase linearly with strain rate in quasi-static tests. With in small dynamic strain rate range, weak rate dependence is observed in SHPB tests, especially at the initial loading stage. The dynamic failure criterion were controlled by stress, and materials failure occurrs at 12MPa. Based on rate-dependent phenomenological material models of solid propellants and rubber materials, one-dimension constitutive equations for quasi-static and dynamic compression are presented, showing a good agreement with experimental data with error less than 10%.