To improve the level of integration and maximize the use of on-board resources by considering the size, mass, and power consumption, a set of integrated electronic system based on reconfigurable software is proposed. By using a distributed functional module and a generic processor, high level of integration, less redundancy, and high function density are achieved without reducing reliability. First, a high computing capability is realized using a high-performance processor with a cold backup processor and an external circuit design. The standardized communication bus among the systems helps in decoupling the dedicated circuits and the general computing and control circuits in the electric power system, altitude and orbit control system, and other systems. Computing and control are achieved using reconfigurable modular software that runs in the main processor. Finally, a test prototype is designed and tested. The prototype consumes less than 2 W of power, achieves computing capability of more than 220 Dhrystone million instructions per second, and fits in a single CubeSat sized printed circuit board that weighs less than 0.2 kg, which satisfies the requirements of high reliability, low power consumption, and ability for expansion needed by micro/nanosatellites. By adding different functions through the system bus, this system can also satisfy other satellite requirements.