Infrastructure-as-a-Service (IaaS) has brought great convenience to users because the virtualization technology hides the details of the physical resoure es But along with the benefits it also leads to the problem that users cant perceive the securiy of the resources This defect has greatly obstructed the cloud c omputing from popularizing and developing To solve this problem.a dynamic measurement protocol in IaaS is presented in this paper This protocolmakes it possible for the user to get real-time sec urrty status of the resoure es.thereby solving the problem that traditional research cannot guarantee the dynamic credibiliy of the resoure es.This changed the security provider of c loud servic e from the operator to the us ers themselves This paper has also verified the sec ury of the protoc ol by means of BAN logic.and the result shows that it c an satisfy the requirements for freshness.privacy and integrity In the end.based on different IaaS platform.this paper has c onducted a performance analysis whic h demonstrates that this protocol is reliable,secure and efficient.