In recent years, people using information technology more to meet their demand for entertainment. For example, on-line game, MP3, on-line TV, movies and so on, which are belong such technology. The increasing of this demand is accompanied the growth of motivation and behavior of piracy. This study focused on recognize and decision pattern of behavior that downloading unauthorized movies, and tried to join the emotion impact, and, understanding college students¡¦ intention of downloading. The research model of this study based on triangle interaction from Social Cognitive Theory (SCT) and its core ¢w Self-efficacy, and developing questionnaire from literature review. The questionnaire measuring the social cognize and personal belief about the behavior which downloading unauthorized movies, and make up an movie with text and post, in order to engagement into the situation, and measuring the impact of intention. The results showed that the research model based on SCT will explain the detail of motivations and decision making about the intention to illegal downloading of common college students, and verified that emotion have the impact in decision making process. According to result, we recommend the irrational factor to research about piracy. For practice, we recommend the preventive of piracy will not only by viewpoint of ¡§crime¡¨ but also by investigate the motivation of piracy.