Hierarchical IPv4 networks put forward higher requirements for the quality of service. This paper analyzes the advantages, disadvantages and the application environment of the traditional QoS architecture based on business according to the second layer and the third layer of the OSI reference model. Then a QoS algorithm integrated differentiated service model with integrated service model is designed to enhance the QoS of a hierarchical network. The simulation results prove that the model can improve the network's QoS in many aspects such as packet loss rate, transmission delay, delay jitter and network throughput.