【Purpose/significance】 Personal information privacy data has the problems of great difficulty in information protection and

low transmission efficiency. In order to ensure the security of users' personal information privacy data, a method for protecting users'personal information privacy data based on big data technology is proposed.【Method/process】 According to the original data of the us⁃ers' personal information, the sensitivity of the information data is detected, the privacy state of the data is obtained, and the users' per⁃sonal information privacy data model is built. After describing the privacy data of the user's personal information, initialize the users' personal information privacy data clustering center, and extract the privacy data for the protection of the user's personal information from the privacy data k-means clustering scheme based on big data clustering technology. By using the double encryption method of privacy information based on dynamic key selection, the extracted privacy data is encrypted to protect the privacy and security of us⁃ers' personal information.【Result/conclusion】 The experimental results show that: under the application of this method, the clustering results of personal basic data privacy data and credit record privacy data are completely consistent with the actual data classification.In the process of extracting and encrypting the users' personal information privacy data in the credit reporting system, the original in⁃formation of the user's personal information privacy data is hidden, and the information loss value of the privacy data is minimal, so the personal information security can be guaranteed.【Innovation/limitation】 This paper studies the protection method of users' personal information in the credit reporting system based on big data technology, which can effectively protect the privacy and data security of personal information in the form of encryption.