Shaped charges are widely used in the field of national defense because of their high energy density and strong directivity; however, one of their limitations is that the penetration diameter is small. Compared with a traditional shaped charge, an annular-shaped charge can create a larger penetration aperture at the target, thereby causing more damage to underwater targets. To enhance the damage effect of a shaped charge on an underwater structure, we designed an annular-shaped charge structure. To end this, we first established a velocity calculation model of the liner and analyzed its formation process. The hydrocode software Autodyn was used to simulate the jet formation process. Second, two parameters of the annular liner height and thickness of the bottom and their effect on the annular jet formation were analyzed. Finally, an experiment was conducted to validate the penetration capability of this charge. The experimental results indicate that the annular-shaped charge can penetrate a typical underwater structure and form a large penetration aperture with a diameter of 420 mm, which is 1.4 times the charge diameter. Furthermore, the numerical results show good agreement with the experimental data; only a 1.67% deviation was observed.