Abstract: Nowadays, more and more users upload their data to the cloud server, since the cloud can provide the service for users any time and at any place. Therefore, the cloud service facilitates the data usability and reduces the cost. However, the information leakage accidents have been reported frequently over the world, that is to say the cloud server is not fully trusted, and the security issue in cloud service must be paid enough attention. For example, illegal user may want to access the cloud server, and perhaps the cloud server does not delete the data according the user’s requirement. In order to address these concerns, a verification scheme for deletion operation in cloud is presented using block-chain technology, which can make the deletion operation more transparent. In our scheme, the user calls the smart contract to prove his identity to the cloud server, and creates the request transaction for data deletion; then the cloud server deletes the data and generates a block chain with the evidence (evidence chain). Even if the cloud server is dishonest, the user can still verify the data deletion result. Moreover, the proposed scheme is analyzed to really achieve the public verification of data without the third-party trusted organization, the impersonation attacks resistance, and the eavesdropping attacks resistance, etc.