The invention discloses a multi-task integrated management system based on an integrated on-board computer, and a processing method. The multi-task integrated management system is used as embedded software and runs in an integrated on-board computer. Using hardware resources provided by the integrated on-board computer, application functions of attitude control, satellite-ground data transmissioncontrol, energy management, temperature control, load imaging condition calculation, on-orbit programming, telemetry acquisition and the like are realized in a multi-task manner. Each of the application functions are assigned to different task modules to realize according to time constraints and access data and other characteristics. The multi-task integrated management system based on an integrated on-board computer is used, each aspect from system, component, circuit, even to devices realizing hardware, software, interface, and communication of the system is designed comprehensively at different levels, to achieve resource sharing, simplify interaction of satellite information flow, improve utilization rate of information resources, and save system overhead.