Abstract: The fuzzy sets theory is applied into QoS-based cloud service selection on the basis of virtual cloud service resource integration. Firstly, attribute tag was realized in Hash algorithm according to users' Qos requirements. The primary candidate service set was chosen from cloud service resource according to attribute tag. Users' preferenes were expressed through fuzzy set theory, and the users' requirement was normalized. At last, the users' degree of satisfaction was worked out, and the cloud service which meets the demard of users' was chosed.