A mobile phone and method for managing short messages of the mobile phone are provided. The method sets a schedule for managing the short messages stored in a storage device, reads a timestamp of a short message when the short message is received, and assigns a first weight value or a second weight value to the short message. The method further generates a message folder according to the timestamp, and classifies the short message into the message folder. In addition, the method checks whether the short message has the first weight value or the second weight value, and backups the short message to the storage device if the short message has the first weight value, or deletes the short message from the message folder if the short message has the second weight value.