Abstract: The RM algorithm has widely been used in hard real-time environment, mainly due to its simple implementation mechanism and low scheduling overheads. However, the heavy system overheads resulting from the highly frequent occurrences of preemption under heavy workload are characterized by the fixed priority scheduling of the RM algorithm. So, a method is proposed to reduce the occurrences of preemption in running due to the scheduling by RM algorithm via optimizing the attribute by off-line computation of task set, thus reducing the relevant overheads. Simulation results show that the occurrences of preemption and relevant overheads in real-time systems can be reduced efficiently by the method proposed without extra scheduling overheads.