The invention discloses a high-reliability energy balance control system for spaceflight and relates to the field of deep space exploration. The system comprises a solar cell array control module, a signal control module and a direct current bus voltage controller. The solar array cell control module comprises a solar controller, a fixed value output module, a two-way switching switch K1, a firstPI controller, a first comparator, a first driving module and a solar cell array voltage stabilizing module. The direct current bus voltage controller comprises a first PI controller, a second comparator, a second driving module and a direct current bus voltage stabilizing module. The energy balance control system is simple and stable in design structure, easy to realize in engineering, capable ofensuring the balance of a spaceflight power system and guaranteeing the high-reliability operation of the system, and the system also has important application value in the field of spaceflight powersupply system regulation.