The explosive characteristics of warhead with and without shell under charge radius of 0.15 m, 0.42 m, and 0.55m are numerically simulated using LS-DYNA software. The characteristic parameters of shock wave pressure and bubble pulsationpressure of the charge with and without shell during underwater explosion are analyzed. Numerical calculation results of different e-quivalents, different charge radius and with/ without shell are compared and concluded. Research results indicate that effect of shellon underwater explosion bubble pulsation is remarkable ; while the thickness of shell does not have much influence on formation timeof bubble, it is of great influence on pressure peak of bubble. Therefore, the shell of warhead must be considered in underwater ex-plosion research