When COVID-19 emerged in China in late 2019, most citizens were home-quarantined to prevent the spread of the virus. This study explored the prevalence of post-traumatic stress disorder (PTSD) and depression in a sample of home-quarantined college students to identify the psychological distress risk factors. The PTSD and depressive symptoms in the 2485 participants from 6 universities were investigated using online survey versions of the PTSD Checklist Civilian Version and the 9-question Patient Health Questionnaires (PHQ-9), and data on sleep durations, exposure, home-quarantine time and socio-demographic variables were also collected. The PTSD and depression prevalence were found to be 2.7% and 9.0%. Subjectively, feeling extreme fear was the most significant risk factor for psychological distress, followed by short sleep durations, being in their graduating year (4th year) and living in severely afflicted areas. Sleep durations was a mediator between exposures and mental health problems. The results suggested that the psychological consequences of the COVID-19 could be serious. Psychological interventions that reduce fear and improve sleep durations need to be made available to the home-quarantined university students, and graduating students and those in the worst-hit areas should be given priority focus.