A touch event processing method of a portable device having first and second operating systems, the method comprising: receiving, at the first operating system, touch coordinates through an application processor "AP" from a touch panel; and if the first operating system determines that the touch coordinates correspond to an icon of a security application: displaying a security keypad on a screen by executing, by the first operating system, the security application, transmitting, by the first operating system, a touch event processing right handover message to the second operating system, commanding, by the first operating system, the AP to change a right of processing a touch event on the touch panel from the first operating system to the second operating system, and receiving, by the second operating system, subsequent touch coordinates in the security keypad from the AP; the method being characterized by further comprising: receiving, by the first operating system, an external event from the AP, the external event being transferred from an external device to the AP by a radio communication unit of the portable device; determining, by the first operating system, whether the first operating system has the right of processing a subsequent touch event; if the first operating system has said right, the first operating system processing the subsequent touch event; if the first operating system does not have said right, the first operating system determining whether any notification image related to the external event is displayed on the screen; if said notification image is displayed, transmitting a touch event processing right withdrawal request message from the first operating system to the second operating system; and receiving, by the first operating system, another touch event processing right handover message from the second operating system, and processing, by the first operating system, the subsequent touch event. receiving, at the first operating system, touch coordinates through an application processor "AP" from a touch panel; and if the first operating system determines that the touch coordinates correspond to an icon of a security application: displaying a security keypad on a screen by executing, by the first operating system, the security application, transmitting, by the first operating system, a touch event processing right handover message to the second operating system, commanding, by the first operating system, the AP to change a right of processing a touch event on the touch panel from the first operating system to the second operating system, and receiving, by the second operating system, subsequent touch coordinates in the security keypad from the AP; displaying a security keypad on a screen by executing, by the first operating system, the security application, transmitting, by the first operating system, a touch event processing right handover message to the second operating system, commanding, by the first operating system, the AP to change a right of processing a touch event on the touch panel from the first operating system to the second operating system, and receiving, by the second operating system, subsequent touch coordinates in the security keypad from the AP; the method being characterized by further comprising: receiving, by the first operating system, an external event from the AP, the external event being transferred from an external device to the AP by a radio communication unit of the portable device; determining, by the first operating system, whether the first operating system has the right of processing a subsequent touch event; if the first operating system has said right, the first operating system processing the subsequent touch event; if the first operating system does not have said right, the first operating system determining whether any notification image related to the external event is displayed on the screen; if said notification image is displayed, transmitting a touch event processing right withdrawal request message from the first operating system to the second operating system; and receiving, by the first operating system, another touch event processing right handover message from the second operating system, and processing, by the first operating system, the subsequent touch event. receiving, by the first operating system, an external event from the AP, the external event being transferred from an external device to the AP by a radio communication unit of the portable device; determining, by the first operating system, whether the first operating system has the right of processing a subsequent touch event; if the first operating system has said right, the first operating system processing the subsequent touch event; if the first operating system does not have said right, the first operating system determining whether any notification image related to the external event is displayed on the screen; if said notification image is displayed, transmitting a touch event processing right withdrawal request message from the first operating system to the second operating system; and receiving, by the first operating system, another touch event processing right handover message from the second operating system, and processing, by the first operating system, the subsequent touch event.