To study the underwater explosion energy characteristics of CL-20-based aluminized explosives with different Al/O ratio, underwater detonation parameters of explosives, including the shock wave peak pressure, the decay time, the bubble pulsation period, the shock wave energy and the bubble energy at 1 m, were measured by a series of underwater explosion experiments. The calculation model of CL-20-based aluminized explosive in the pool was established by using Ansys LS-DYNA software and was calculated the shock wave energy and bubble pulsation period. The results showed that Al/O ratio significantly changed the energy output structure of CL-20-based aluminized explosives. With increasing Al/O ratio, the proportion of shock wave energy in the total energy decreased, while the proportion of bubble energy increased.When Al/O ratio was 0.35, the shock wave peak pressure and shock wave energy of the explosive were the largest, and when the ratio was 0.6, the bubble period and total energy reach their maximum; when the ratio was 0.94, the bubble energy and the bubble pulsation reached the maximum. The experimental values are in good agreement with the simulation results, and the model can be used to estimate the underwater detonation parameters of CL-20-based aluminized explosives with different Al/O ratio.