Li-Ion Battery is getting more and more recognition and application for its predominant capability, but it requires highly for safeguard circuit. The peculiarity of Li-Ion Battery is expatiated, and single-chip 8031 is adopted as a safeguard to protect and control the charge and discharge of Li-Ion Battery due to its peculiarity. The safeguard method and advertent problem of Li-Ion Battery are analyzed and the application circuit is presented. A reference is provided for the application of Li-Ion Battery charge and discharge safeguard circuit base on single-chip system.