People currently regard justice as the main principle of institutions and society, while in ancient Greek people took it as the virtue of citizens. This article analyzes Aristotle’s virtue of justice in his method of virtue ethics, discussing the nature of virtue, how justice is the virtue of citizens, what kind of virtue the justice of citizens is, and the prospect of the virtue of justice against a background of institutional justice. Since virtue can be said to be a specific individual character, Aristotle also defines the virtue of justice as the character of justice, with which citizens act justly and desire to do what is just. The virtue of justice is also an individual ethical virtue, differing from others for it is at the same time a social ethic. We can call the virtue of justice a “non-individual individual ethical virtue.” It has been explained as between pure altruism and egoism, which is a wrong explanation. John Rawls regards justice as the first virtue of social institutions, challenging Aristotle’s virtue of justice, an assertion which also needs further deliberation.