Abstract: The present invention relates to the touch-screen mobile device provides a better user experience by enabling a true one-hand operation, as the user can hold the mobile device with one hand and operate the device with the thumb of the same hand. The present invention is comprising: a touch screen; an arc-shaped user interface, displayed on the touch screen, which takes one corner of the touch screen as its center; and a control part that detects user' touch actions such as tap, multiple-taps, swipe, drag, or hold & drag, and processes the user' feedback accordingly.