(Regarding this issue, a dynamic QoS guessing method based on case-based reasoning (CBR) is proposed, which correlates the QoS of Web services with the external environment of the service, the types of tasks managed, and the size of the tasks, and uses case-based reasoning technology to guess. QoS when the web service manages new tasks. The experimental results show that the conjecture method can effectively improve the accuracy of Web service QoS.)