Objectives: The purpose of the study is to investigate the significant(SiC) index of the 12 year old children`s permanent teeth caries experience. A total of 428 children aged 12 years old were recruited from metropolitan city(215 children) and rural area(213 children) in this study. SiC index was obtained from DMFT index. Data were analyzed by gender, region, and DMFT. Methods: DMFT index and Sic index were analyzed and compared by pit and sealant fissure treatment, dental caries, gender, and areas. A total of 428 children aged 12 years old were recruited from metropolitan city(215 children) and rural area(213 children) in this study. Results: Boy students(6.73) tended to have a higher SiC index than girl students(7.84). There were significant differences(p<0.05). DMFT index in urban area was 2.59, and that in rural area was 3.35. In SiC index, rural children showed a higher index(7.77) than urban children(6.72).There existed a significance between DMFT index and SiC index(p<0.05). Conclusions: It is important to educate and to develop the oral disease prevention program for the high risk group children. This study showed the relationship between DMFT index and SiC index in 12 year old children in urban and rural areas.