How to audit the integrity of data stored on the cloud with incomplete trust is an important problem that restricts the development of cloud storage. Although there are several data integrity audit schemes in cloud storage, the increased need to protect sensitive information and support large-scale data storage and dynamic update will result in a significant increase in audit cost, which seriously affects the efficiency of existing cloud audit systems. To solve this problem, we propose Ldasip, a lightweight dynamic auditing method that supports sensitive information protection in cloud storage. Exploiting identity-based data integrity audit, a data masking technology is introduced into to protect user’s sensitive information. At the same time, an improved multibranch tree structure is proposed to realize dynamic audit and reduce communication overhead in the verification process. Theoretical analysis and comprehensive experiments have been conducted, which demonstrate the effectiveness of Ldasip. The results show that Ldasip can ensure the correctness of the audit, protect the sensitive information in the user's stored content, and support the dynamic update of data with less audit time and communication overhead.