In response to the requirements of large optical remote sensing satellites for high reliability, high performance and ease-touse, an integrated electronic system with high fault tolerance is presented. The design of system architecture and information flow are showed, and the key design technologies such as satellite operation management and system fault tolerance mechanism are discussed exhaustively. The on-orbit application of the designed integrated electronic system on a certain satellite is introduced. The satellite fully adopts the multi-redundant backup architecture, fault-tolerant technology and operation management technology proposed in the paper, and completes 21 imaging and 11 transmissions per day on average. The average daily shooting area is as high as 1. 1 million square kilometers, and the longest continuous trouble-free operation time is more than 6 months, which fully verifies that the designed integrated electronic system has the ability to operate efficiently and stably in orbit.