The invention relates to a time-varying computer based on a reorganization technology, and an on-board time-varying computer is formed by adopting the structures of a processor unit, a configuration unit and a radio frequency unit, the computer can realize the automatic switching function according to the mission of the satellite by a FPGA hardware program. The invention has strong processing capacity as the hardware program is adopted to realize the system function; meanwhile, the reorganization technology leads the time-varying computer to realize the fault tolerance function for each on-board computer, which avoids the influence on the satellite caused by the various hard wares of the system; at the same time, the time-varying computer can be upgraded on line.