Under the traditional static resource reservation mechanism (SRRM), once a user’s reservation request has passed the admission test, it is scheduled for a certain resource immediately. SRRM considers neither the impact of the resource change on the schedule target nor the impact of resource error on the reservation in the book-ahead time. A dynamic resource reservation mechanism (DRRM) is presented, in which the accepted reservation requests are scheduled during the consumption the resource. The resource-reservation graph (RRG) is introduced to describe DRRM, and the modification rules of RRG have also been presented. The simulation experimental results show that though DRRM loses some admission percentage, it considerably decreases task preemption, dramatically improves the resource utilization, and has a better capacity of fault tolerance to the resource error ratio.