The composition of burning gases and energetic properties of hydroxylamine nitrate （HAN） based underwater monopropellants were calculated by balance constant method, D₁ with formula of HAN/dioxane/water=59.15/10.85/30.00 were burned in the liquid regenerative closed bomb,and the effects of different charge densities on combustion properties were analyzed qualitatively. The energetic characteristics and surface wake of D₁ propellant were analyzed and compared to that of LP1846 and OTTO-Ⅱ propellant. The results show that the specific impulse and characteristic velocity of D₁ propellant come up to 2343.53 N·s·kg^-1 and 1466.32 m·s^-1 respectively,higher than LP1846′s 2157.99 N·s·kg^-1 , 1341.04 m·s^-1 and OTTO-Ⅱ′s 2038.52 N·s·kg^-1. Moreover,the water-soluble gas products of D₁ propellant come up to 77.7% of the total molar mass of gas products,therefore,the surface wake of D1 propellant is smaller and concealment characteristic is better than that of OTTO-Ⅱpropellant.