Effects of azide polymers on the sensitivities and fragmentation mechanism were studied in this paper. Only fragmentation was observed at lower impact velocity, up to 172 m/s, even with an one-kilogram impactor. Most of the propellants showed linear relationship between an impact velocity and fragmented fraction. The critical impact velocity, V-cr, depended on the amount of the binder but not on the chemical structures. The propellants which had no particle oxidizers showed high V-cr and their cracks were hard to grow into a piece of fragment. Nitramine-binder matrix dewetting caused by deformation of the propellant was supposed to terminate the crack propagation and to damp the impact energy at a higher impact velocity. In AP-based propellants impact velocity dominated the initiation mechanism and impact energy did not control the ranking of the reaction. The friction energy played a more important role in the initiation than did the impact energy. There was no difference in the sensitivity to the card gap test between the azide polymer and HTPB binder.