Abstract: According to the need of DiffServ model and based on the analysis of present buffer manager algorithms, QPRED and VPRED multi level buffer manager algorithms are put forward. The two algorithms provide the grade of buffer manager at the granularity of packer classification, and induce buffer state （queue length or average queue length） of every packet classification into calculation of the probability of packet drop. At the same time, integrating priority paramater, the two algorithms realize fairness at the meaning of priority. Comparing with the present buffer manager algorithms, QPRED and VPRED algorithms are more fit to DiffServ model.