The basic question of this study was to investigate the process of moral decision-making: which components influence the decision and why do some people make moral decisions more often than the other people. In this research 'utilization' and 'domain' are the important factor for moral decision-making. The 'utilization' refers the degree of people's using moral judgment information in their decision-making. The logic behind the U score is that if we know the particular items selected in the DIT as important by a person then by the logical implications of that item, we can determine which action is more appropriate for the subject. Simply, U score is the degree of matches between actual choices and predicted action choice by the item selections. The 'domain' refers to different 'thought forms'. Moral domain refers to objective obligation concerning justice, human welfare, and right(e.g. hitting, stealing, hurting). Conventional domain refers to uniformities in social behavior (e.g. mode of dress, manners, sex roles). Personal domain affect primarily the actor(choice of friends, hobbies, actions which focus on the state of one's own body). Eighty two families were participated to complete the two questionnaires(DIT and a story test for domain use). In each family, a high school student, a college student and one of their parents were involved. First, the study examined the relationship between action choice and domain use in the justification of the action chosen. Half of the stories had significant relationships. Secondly, the study examined the relationship between domain use and utilization score. Results indicated that moral domain users were high utilizers. These results were considered to have both methodological and theoretical implications for the study of morality.