The principle of equality prescribed by Article 7 of the Constitution does not mean a formal equality in an absolute and mechanical sense. Rather, it aims to guarantee the substantive equality of the people in the sense of equal protection under law. The legislative body, based on the value system of the Constitution and the purpose of enactment, could consider the differences of the addressed subject areas and reasonably treat them differently. This study aims to explore and build the standards of judicial review concerning the principle of equality that have been applied in the ROC Constitutional Court.