A method of controlling temperature of a fuser of an image forming apparatus includes measuring the temperature of the fuser, comparing the measured temperature with a previously measured temperature and determining whether the temperature of the fuser is ascending or descending to differentiate a temperature ascending stage and a temperature descending stage from each other, and controlling a chopping rate of the switching unit that intermittently connects power to the fuser. Reducing unnecessary power consumption is possible because the temperature of the fuser is controlled by differentiating a temperature ascending stage and a temperature descending stage from each other, and the quality of image may be enhanced and a flicker phenomenon is prevented.