In order to study the detonation performance of propellant grains in different medium, the interspaces among the propellant grains were fully filled with water, oxidant solution and oxidant gel, respectively. The detonation performances of propellant charges with different filling medium were studied through the plate dent test and chronometer measurement test, which compared with no filler. The underwater output energies of propellant charges containing different oxygen balance of filling fluids were also measured by underwater blast test. The results show that with the addition of different filling medium such as water, oxidant solution in the charge of propellant grains, it is conducive to the growth and spread of detonation shock wave. The work capability of the charge is improved, and the detonation velocity is also increased. When the charge of propellant grains is filled with the dense medium which contains oxidant, it has excellent detonation velocity(about 6.4 km·s^-1).The underwater energies of propellant charges are increased with the increase of the oxygen balance, and there is a significant linear relationship between the total energy and the oxygen balance of the charge. Its shock wave energy is more than 1.0 kJ·g^-1 and the total energy is basic quite compared with the rock emulsion explosive and ammonium nitrate-fuel oil explosive.