In order to research the damage effect of semi-armor-piercing warhead charge explosion on combined cabin of vessel, the finite element software ANSYS-DYNA was used to simulate the process of internal explosion. The damage effect of semi-armor-piercing warhead charge explosion was evaluated through analyzing distribution of explosive flow field, pressure variety under explosive loading in cabin and the failure mode. The results show that semi-armor-piercing warhead charge can cause efficient damage to combined cabin; the interaction of shock waves of two-stage charge explosion can increase the peak value of shock waves pressure and quasi-static pressure in cabin, enhancing damage ability to the cabin. The results can provide reference for damage evaluation of combined cabin of vessel.