This application provides a memory management method and a terminal device. According to the method, a frequently accessed memory page and a rarely accessed memory page that are required for starting and using an application may be determined by using a memory page on which a page exception occurs in a target running application. A terminal retains, in a memory, the memory page that is required for starting and using the application, to resolve a problem that freezing occurs when an application that runs in a background is started again, and improve keepalive performance of the application. The terminal migrates the rarely accessed memory page to a swap partition of a storage, to save memory resources.