Scheduling is to determine when and on what processor each process has to run. Scheduling objectives are achieving high processor utilization; minimizing average (or maximum) response time, maximizing system throughput, and being fair (avoid process starvation).Many scheduling have been introduced in order to optimizing the processor utilization. One of this algorithm is Round Robin CPU scheduling (RRCS) .We optimize RR by using the concept of fuzzy rule base system. We introduced a new fuzzy algorithm called fuzzy rule based round robin CPU scheduling (FRRCS) .The rules are extracted from the knowledge of experts and they are experimental. The advantage of FRRCS is compared with the RRCS. It is shown that the FRRCS algorithm is improved the waiting and response times.