Disclosed is an image forming apparatus which forms an image including an image forming unit to form the image on a paper, a plurality of paper ejection trays to mount the paper on which the image is formed, a display unit to display a setting screen for selecting at least one paper ejection tray for a reserved job among the paper ejection trays, detecting units to detect a present mounting amount of the paper in each paper ejection tray and a control unit to control the display of the setting screen, and the control unit simultaneously displays the detected mounting amount of each paper ejection tray on one setting screen.