A real-time scheduling apparatus and method for suppressing battery aging of a satellite system are disclosed. A real-time scheduling method for suppressing battery aging of a satellite system according to an exemplary embodiment of the present disclosure may include acquiring task information including a request period and an execution time of each of a plurality of tasks which is performed in the satellite system; determining an execution limit range and an execution order for each of the plurality of tasks which satisfies a predetermined real-time constraint based on the task information; and determining an optimal execution timing within the execution limit range of each of the plurality of tasks, based on the execution order and consumed current information of each of the plurality of tasks.