["\nAbstract\nPrisoners' affective education is a hot topic in criminal psychology. The lack of the social support for prisoners means that they are more prone to loneliness. The mental health status of the prisoners directly concerns their social adaptation when released. We therefore explored the relationship between loneliness, psychological affect, and control source in 201 prisoners. Prisoners completed the state and trait loneliness scale, the affectal scale, the internal control, powerful others, and chance scale. Mediation effect analysis was conducted to explore the mediation role of the control source from influence of loneliness on psychological affect. State loneliness indirectly affected positive affect through internal control factors. Trait loneliness directly affected negative affect, and trait loneliness indirectly affected negative affect through opportunity factors. Overall, this study uncovers some of the psychological mechanisms underlying emotional state in prisoners, highlights the need for effective psychological correction programmes in the prison system and provides reference for effectual ascension of prisoners out of jail.\n", "Journal of Investigative Psychology and Offender Profiling, Volume 17, Issue 2, Page 93-100, June 2020. "]