Abstract: Disclosed is a method of inputting a character in mobile devices. A simultaneous pressing, an overlapped-pressing, a long-and-short continuous pressing of two buttons, and a double-click of one button are employed to input as many letters as possible in a fast and convenient mode using a limited number of buttons, thereby improving use of buttons. In the input buttons of mobile devices, each button is assigned with one character and at least one character is assigned to between two neighboring buttons, such that the assigned letters can be input through a simultaneous pressing, an overlapped-pressing, or a long-and-short continuous pressing of two neighboring buttons.