Abstract: Hydroxyl-terminated polybutadiene (HTPB) solid propellants are widely used in solid rocket motors due to their excellent mechanical properties. However, accidental drops during the assembly process may cause failure of the propellant charge structure integrity, posing significant safety risks. This study established a dynamic response simulation model of the propellant under drop impact loads based on the viscoelastic statistical crack (Visco-SCRAM) constitutive model, and systematically analyzed the influence mechanism of different drop conditions on the safety of the propellant charge structure. The numerical simulation results show that the drop height and landing angle are the key factors affecting the safety of the HTPB propellant charge structure. The critical safety heights for 90° vertical drop, 45° oblique drop, and 0° horizontal drop are 42.05 m, 28.8 m, and 9.8 m, respectively. The research results confirm that the Visco-SCRAM model can accurately describe the drop impact response of HTPB propellants from both qualitative and quantitative perspectives, providing a scientific basis for the safety protection design during the assembly process of solid rocket motors (such as setting drop height limits and optimizing buffer structures), and also offering a reference for the development of dynamic safety assessment models for energetic materials.