The invention discloses a low-temperature propelling system. The low-temperature propelling system comprises a first storage box and a second storage box; a first isolating valve is arranged at the outlet of the first storage box; a second isolating valve is arranged at the outlet of the second storage box; and the low-temperature propelling system also comprises an internal combustion engine, anattitude control engine, a bottom engine and an orbit changing engine. The low-temperature propelling system solves the technical problem that waste of a propellant is liable to occur in the low-temperature propelling system. The low-temperature propelling system so simplifies the separate propellant supply system and pressurization system of the attitude control engine and reduces the dry weightof the propelling system. In addition, propellant steam in a steam cooling screen serves as a fuel battery working medium and the internal combustion engine is used for driving an electric generator,so that the electricity demand of the propelling system work is relieved.