The library circulate apartment service system in a high school is inferred as a solid example. An operation model of this system is established.According to the assumption  of the queuing theory ——a single stage service or one stage in series services is independent respectively. The Witness 2003 advanced simulation technique is used to build up simulation  model of the existing service system,so the internal factor（the efficiency of the service system）and the external factor(the service request from the reader flows in the books stack )which influence the queuing system directly or indirectly, are integrated well. Based on the service system performance parameter’s reports in one clock-time, the optimal analysis is made,and  one feasible optimal project is put forward combined with the real problem of resources rare.