With the rapid growth of cloud storage data, the proliferation of redundant and duplicate data has become increasingly prevalent. In order to reduce the waste of space on cloud storage servers, providers of cloud storage services have tried to delete duplicate data to save space. However, it is imperative that the deduplication process be conducted with due consideration for data privacy, as users seek to safeguard their sensitive information. In this paper, homomorphic encryption, label calculation and de-weighting of uploaded images are carried out to achieve the purpose of privacy protection. In this process, homomorphic encryption, computing file level hash tags and other core methods are used to realize a complete data cloud storage system. The system ensures the security of data by homomorphic encryption of pictures uploaded by users. And with the help of Baidu intelligent cloud picture audit, to ensure the legitimacy of the picture, and dynamically remove the weight of the file in the whole process, reduce the waste of cloud storage space.