Criterions for judging the dynamic stability of bulkheads in underwater explosion are presented, including the B-R criterion based on the charge weight, the B-R criterion based on the standoff distance and the B-R criterion based on the new impact factor. The dynamic stability of bulkheads of a certain warship is calculated with these criterions, and it is found out that the bubble pulsating loads can not be ignored in the stability analysis. The stability of the structure is separated into three stages. Besides, the collapsing loads and the collapsing modes in different attack angles are computed, and some laws are obtained which offers some valuable references to engineering.