A method and an apparatus for executing applications in a highest-priority-first order in the processor divided into a secure mode area and a non-secure mode area are provided. The method includes receiving a request to be processed in the non-secure mode domain from the application, determining an access permission level configured to a resource used for processing the request, determining, when the access permission level allows for access from the secure mode domain, a priority of the application, changing the access permission level to allow for access by the non-secure mode domain according to the priority of the application, and processing the request of the application using the resource in the non-secure mode domain.