A user interface apparatus and method of using a touch screen are provided. The apparatus includes a touch screen division unit for dividing a screen area of the touch screen into zones, an allocation unit for allocating a user interface unit to each of the zones and a plurality of user interface units for sensing job commands input through the zones according to the allocation result of the allocation unit, wherein an operation corresponding to each of the sensed job commands is performed. Accordingly, since a plurality of users can simultaneously use an image-forming device by dividing the screen area of the touch screen into two or more zones, job processing time can be reduced, and a usage rate of a high specification image-forming device can be increased.