Abstract: A tasks assignment algorithm for the distributed fault-tolerance system is presented, we considered the periodicity, redundancy,adaptability and importance degree of the simulation system tasks and the load balancing of the processors in the algorithm. The algorithm achieved the redundant distribution of the system tasks by three steps of static tasks assignment and distributed the active, passive and sleeping copies of one task to different processors. The system would change the task's state and realize system reconfiguration by dynamic awakening algorithm of redundant tasks in case of the processor failure. The redundant tasks assignment algorithm can achieve the dependability requirement of the simulation system, at the same time, it can ensure the system real-time performance.