To understand the effect of additives on mechanical properties of Comp.B, six formulations of modified Comp.B(B-1, B-2, B-3, B-4, B-5 and B-6)were prepared by addition of thermoplastic elastomer(VP-401 and VP-501) of mass percentage 2%, thermosetting resin polymerized by pentaerythritol and acrylic aldehyde /diethyl sulfate(123 resin/DES) of mass percentage 1% or 3%, hydroxyl-terminated polybutadiene/diphenyl methene-4, 4′diisocyanate (HTPB/MDI) of mass percentage 5% in solidifying coefficient 0.6 and 0.8, respectively. The compression test、Brazilian test and split Hopkinson pressure bar(SHPB) test were performed.The stress-strain curves of modified Comp. B in static compression, indirect tensile and low speed impact were obtained.The elasticity and toughness changes of modified Comp.B were compared and analyzed. Results show that compared with Comp.B, the compressive elastic modulus of B-1 and B-2 explosives increase by 1.49 GPa and 2.28 GPa, respectively. The compressive strength of B-1 and B-2 explosives increase by 6.7 MPa and 6.3 MPa, respectively. Their elasticity and toughness of compress are better than those of Comp.B. When strain rate 50 s^-1. Compared with Comp.B, the dynamic compressive strength of B-3 and B-4 explosives increase by 1.9 MPa and 7.6 MPa, respectively, while the dynamic compressive strength of B-5 and B-6 explosives decrease by 8.33 MPa and 19.47 MPa respectively. Results show that the low speed impact-resistance ability increases for B-3 and B-4 explosives and reduces for B-5 and B-6 explosives.