With the advent of the era of big data, the information that people come into contact with on a daily basis is gradually being comprehensively collected and used. Thanks to the use of big data, it is possible to significantly improve the development space of various industries in our country and provide good services to network users. However, when using big data applications, the security of personal information has also been severely affected, and the leakage of personal information is relatively simple. In order to ensure the security of personal information more effectively in the era of big data, this article provides an appropriate analysis of the main characteristics of obtaining and collecting information in the era of big data in combination with the main manifestations of personal information security problems. A comprehensive analysis was also carried out from the point of view of legal protection, and at the end of the article targeted measures were proposed to counteract the legal protection of information security of personal information, in the hope of gradually increasing the level of legal protection of information security of personal information in big data. era.