Laws do not violate the principle of proportionality if they have the due purposes, necessary means, and proper restrictions required by Article 23 of the Constitution. In other words, if the legislature chooses a means to an end and considers that the means will be helpful to the achievement of justifiable legislative purposes, and that there is available no other alternative means to attain the same purposes with less harm, the law should not be deemed to be inconsistent with the principle of proportionality embodied in Article 23 of the Constitution insofar as the restriction imposed by the means on the fundamental right is proportional to the importance of the legal interest intended by the lawmakers to be placed under protection. This study attempts to explore the standards of judicial review concerning the principle of proportionality that have been applied in ROC Constitutional Court, and tries to figure out our own ways.