The purpose of this research is to examine the attitudes and behaviors on cannabis use from the perspective of users, and hopes to provide corresponding advanced countermeasures against current differences in concepts and seizure policies. Analyzing data from in-depth interviews with 4 users from 3 corrective agency and 4 users who have not been seized. The research found that users hold positive and supportive views on the harm and legalization of cannabis; based on their own experience, they don't think it will be easily intercepted and will not cause abnormalities after use. Finally, based on the research findings, provide corresponding suggestions in order to reduce social conflicts and establish consensus standards, and improve the investigation policy to reduce the occurrence of the dark figure of crime.