A mathematical model of Perfusion Chemostat（PC） system is developed by using continuous feedback processes, where dilution rate is no longer equal to specific growth rate. It is found that specific growth rate is strongly related with dilution rate. Mammalian cell density in the bioreactior can indirectly be predicted and estimated by employing growith model as a function of dilution rate. The maximum specific growth rate is 0.019(1/h) at 0.020(1/h) of dilution rate. The recycle ratio, α and concentration factor, f are extimated as 0.01 and 90.21, respectively. These values are proved to be important parameters in controlling PC system to effectively cultivate large quantities of mammalian cells and produce pharmaceutically active proteins.