Scheduling condition and algorithm analysis of task sets which task deadline is not less than its period was introduced. This restrict conditions is slackening, and it is good for scheduling of mixed model of period and no-period task. At the same time, scheduling restrict conditions of original RM algorithm was analyzed and the shortcoming of computing time complexity was pointed out. Then a real-time scheduling approach and implementing flow-chart based on RM algorithm was presented, and a strict contrast test of the real-time scheduling approach was given.