The optimization of service systems is inseparable from the study of queuing models, involving the establishment of models and the comparative analysis between them. First, the general models of the queuing system are introduced. The queuing system is assumed to be M/M/1 model and M/M/c model, in which the customer arrival is Poisson flow and the service time is negative exponential distribution. As any complex queuing model is derived from these two models, they are widely applied in service systems such as production and daily life. Second, in order to enhance the contrast between the two models, the two kinds of models are refined into three comparable cases, and average queuing time models are established separately. Finally, through theoretical derivation, software simulation, and theoretical testing methods, the comparison results of these three queuing models under the Poisson arrival process are obtained, which is of paramount importance for the practical application of queuing models.