To study the initiation/detonation characteristics of the shelled cast-cured polymer bonded explosive(PBX) caused by shaped charge jet, the impact test of the PBX explosive, overlaid by two groups of steel plates with thickness of 210, 255 mm and 165, 210 mm, was performed respectively by shaped charge with different forms and jet velocities, produced by the shaped charges with diameter of 82 mm, that is a small diameter and velocity is greater than 7000 m·s^-1 high-speed jet, another thicker diameter and about 5000 m·s^-1 jetting projectile charge.The shock initiation and detonation processes of the PBX explosive were observed and analyzed by high-speed photography.The experiment results were verified by LS-DYNA software.The values of initiation/detonation energy of the PBX explosive caused by different jets were obtained.Results show that jets formed by shaped charges with diameter of 82 mm can reliably cause the shock initiation and detonation of the PBX explosive overlaid by steel plates with thickness of less than 255 mm, can meet the needs of anti-missile warhead to damage the thick shell target.