The present invention provides an apparatus for converting a video format of a digital TV and method thereof, by which various functions such as video format detection, color space conversion, chroma format conversion, gamma correction, geometric correction, image quality adjustment, and the like are implemented on one chip to support video signals of various specifications and display devices. The present invention includes an input video format detecting unit detecting a format of an input video, a format converting unit converting spatial resolution, frame rate, scan, aspect ratio, color space, and chroma format of the input video signal detected by the input video format detecting unit into a requested output format, a display characteristic correcting unit correcting the signal converted by the format converting unit to fit a display device, and an image quality adjusting unit adjusting an image quality of the corrected signal.