Smartphones are convenient tools for modern people, but apps often violate users' privacy rights. Given the vast reach of the Internet, personal information can be transmitted to any corner of the world, resulting in more unpredictable information security incidents. Therefore, the protection of personal privacy in the digital world deserves further attention. This article intends to use the APP of PX Mart's members familiar to consumers combined with the PXPay Plus APP as an example to illustrate the digital privacy risks that smartphone users may encounter. In addition to basic personal information, financial data, consumption data, and daily location tracking all are recorded in network system for big data statistics, and then for commercial advertisement placement. This article intends to outline possible protection mechanisms.