The wavy extinction of quartz can be used as a standard indicator showing the degree of rock deformation. To determine the degree of rock deformation, the intensity of wavy extinction (IWE) of quartz was measured using petroggraphic microscope, digital camera, and NIH image. In this study, this method was applied to the Cheongsan porphyritic granite, Cheongsan two mica granite, and Baekrok granite to investigate the deformation intensity of Cheongsan area. NIH Image data show a high-grade deformation in the vicinity of the strike-slip fault (between Cheongsan granite and Baekrok granite) and the unconformity (between Cheongsan granite and Youngdong basin). Thus, the main deformation in these areas is most likely to be concentrated on the faults that generate Yeongdong basin and the strike slip faults between Cheongsan granite and Baekrok granite.