Comp.B was modified by adding 2% thermoplastic elastomer 401 and 501. For the MB-1 and MB-2 of modified Comp.B, mechanical properties and drop hammer impact sensitivity were tested, detonation performance was calculated by using experience method and VLWR code. Results show that the elasticity and toughness of the MB-1 and MB-2 were better than that of Comp.B, the toughness of MB-2 were better than that of MB-1 in low speed impact experiment. In drop hammer impact test of big-bill explosives, the threshold heights of ignition for the MB-1 was 3.5 m to 4 m, for MB-2 it was 6 m to 6.5 m. The impact sensitivity of MB-1 was higher than that of MB-2. Compared with Comp.B, the CJ velocities of the MB-1 and MB-2 decrease by about 0.104 mm·μs-1 and 0.099 mm·μs-1, respectively; the CJ pressures of the MB-1 and MB-2 decrease by about 1.3 GPa and 1.2 GPa,respectively. 