The invention provides a control method of an application program, a control device and a terminal. The control method of the application program comprises the following steps: monitoring number of application programs running in the background; and closing at least one application program running in the background when the number of the application programs running in the background is larger than a number threshold. According to the technical solution of the invention, the application programs running in the background can be cleared automatically, so that running fluency of the terminal is ensured, and therefore user experience is improved.