Enterprise Service Bus is a flexible infrastructure to integrate applications and services. Quality of Service (QoS) is an important measurement of the Web service’s quality. According to the analysis issues of the existing QoS evaluation system, we design and implement a QoS evaluation system based on the ESB, which uses the functions and information of ESB properly. This system does not only reduce the complexity of modular design, but also improves the performance of evaluation system’s capability. The result shows that the quality of service evaluation system has a better performance in the situation of heavier load.