With the improvement of microsatellite technology, microsatellites with high functional density, low cost and rapid development have become research hotspots in the modern aerospace field. However, the traditional electronic system in the microsatellite is low in integration. The wiring between boards is complicated and the reliability is low. Due to the mutual constraints on quality, volume, power consumption, and performance, it is gradually unable to meet the development requirements of microsatellites. The proposed onboard integrated electronic system for microsatellites has achieved an overall improvement in reliability, power consumption and performance under the condition of limited size and quality. This article describes the development history and research status of the integrated electronic system of microsatellites. Then, it analyzes the key technologies applied in the general and flexible design of the integrated electronic system of micro-satellites. Finally, it summarizes current challenges and future development trend.