Using the survey of students from colleges of business/management, this study uses business simulation scenarios to investigate possible determinant factors affecting students' making ethical-decisions, based on ethical decision-making process theory and issue-contingent model, from moral philosophy and ethical issues (moral intensity) perspectives. Valid samples totaling 1,082 were collected to undertake analysis. Empirical results suggest that the more one's perception of moral issues, the more likely he or she passes on moral judgment, thus further leading to higher moral intent. Moral intensity and ethical-decision making process are positively correlated. In addition, when facing an ethical dilemma, the ethical decision-making processes of Idealism-prone students are more likely to be mediated by moral intensity, whereas the ethical decision-making processes of Relativism-prone students are less significantly mediated by moral intensity. Finally, students majoring finance have significant higher relativism tendency than those majoring accounting and business management.