Abstract: ueueing is a very popular and very important phenomenon in engineering and society.The analysis and study of it will contribute to solve a lot of problems in comlllunicati on. computer.aerospace and ECM. The Queueing theory has go some imp ortant results in aboye mentioned fields.Queueing simulation cixn compensate Queueing theory for its limits.A new definition of queue system has been offered in the paper.Review and snalysis of the previous results of Queueing theory are given three limits of Queueing theory are presented, and that essence of queueing simulation is in fact a digital filtering is p ointed out.