A data processing method in a system including a digital TV (110; 200, 300; 600; 720; 820; 920; 1010), a mobile terminal (115, 120, 130; 400, 500; 610, 620, 630; 710; 810; 910; 1020) and an external server (105, 830), the data processing method comprising the steps of: pairing the mobile terminal with the digital TV, wherein the mobile terminal (115, 120, 130; 400, 500; 610, 620, 630; 710; 810; 910; 1020) and the digital TV are each directly connected with an external server; executing a digital TV control application in the mobile terminal; selecting, in the mobile terminal, a specific application via the executed digital TV control application and transmitting a control command including data on the selected specific application to the digital TV, wherein the specific application is to be executed in the digital TV; requesting, in the digital TV, application data from the external server; collecting, in the external server, the corresponding application data in accordance with the request and returning the collected application data; executing, in the digital TV, the specific application on the basis of the application data returned from the external server; receiving, in the mobile terminal, the application data executed in the digital TV and providing the same application execution screen; determining, in the digital TV, an attribute of at least one menu if the mobile terminal requests the at least one menu through the executed digital TV control application; if an attribute of a first menu corresponds to a function of a corresponding application or application list, (i) requesting, in the digital TV, first menu data from the external server, and (ii) receiving, in the mobile terminal, the first menu data directly from the external server; if an attribute of a second menu corresponds to an OSD menu capable of being provided by the digital TV, receiving, in the mobile terminal, second menu data from the digital TV; and displaying, in the mobile terminal, the first menu data or the second menu data while the digital TV does not display any menu data. pairing the mobile terminal with the digital TV, wherein the mobile terminal (115, 120, 130; 400, 500; 610, 620, 630; 710; 810; 910; 1020) and the digital TV are each directly connected with an external server; executing a digital TV control application in the mobile terminal; selecting, in the mobile terminal, a specific application via the executed digital TV control application and transmitting a control command including data on the selected specific application to the digital TV, wherein the specific application is to be executed in the digital TV; requesting, in the digital TV, application data from the external server; collecting, in the external server, the corresponding application data in accordance with the request and returning the collected application data; executing, in the digital TV, the specific application on the basis of the application data returned from the external server; receiving, in the mobile terminal, the application data executed in the digital TV and providing the same application execution screen; determining, in the digital TV, an attribute of at least one menu if the mobile terminal requests the at least one menu through the executed digital TV control application; if an attribute of a first menu corresponds to a function of a corresponding application or application list, (i) requesting, in the digital TV, first menu data from the external server, and (ii) receiving, in the mobile terminal, the first menu data directly from the external server; if an attribute of a second menu corresponds to an OSD menu capable of being provided by the digital TV, receiving, in the mobile terminal, second menu data from the digital TV; and displaying, in the mobile terminal, the first menu data or the second menu data while the digital TV does not display any menu data.