Two kinds(casting moulding and pressed fitting) of HMX-based anti-overloaded explosives were chosen to study the damage characteristics and damage failure mechanisms of explosives under overloaded conditions by shock loading. The shock damage was conducted based on shock wave sensitivity test. The damage characteristics of samples before and after shock loading were studied by CT and the shock wave sensitivity was also tested after damage. Results of CT test show that no macro-damage appear in explosive by pressed fitting after the shock damage, while a cavity with length of 7-8 mm and diameter of 1-2 mm appears in cast explosive and is located at 7-8 mm away from one end of the witness board. After shock damage experiments, for cast explosive, above the position of 40 mm from the bottom surface, the explosive density decrease by 1%-5%, and for the pressed fitting explosive, above the position of 50 mm from the bottom surface, the explosive density increase by 1%-8%. The shock wave sensitivity of the both samples decreases after shock damage. The critical gap thicknesses of the cast explosive decreases from 25-27 mm before damaged to 13-15 mm after damaged, while for pressed fitting explosive, the thickness decrease from 38-40 mm to 30-32 mm.