Objective We developed easily accessible imagery-based treatment program for patients with post-traumatic stress disorder (PTSD) related to workplace accidents and investigated the effects of the program on various PTSD related symptoms. Methods The program was based on an online platform and consisted of eight 15-min sessions that included script-guided imagery and supportive music. Thirty-five patients with workplace-related PTSD participated in this program 4 days per week for 4 weeks. Its effects were examined using self-report questionnaires before and after the take-home online treatment sessions. Results After completing the 4-week treatment program, patients showed significant improvements in depressed mood (t=3.642, p=0.001) based on the Patient Health Questionnaire-9 (PHQ-9), anxiety (t=3.198, p=0.003) based on the Generalized Anxiety Disorder seven-item (GAD-7) scale, and PTSD symptoms (t=5.363, p<0.001) based on the Posttraumatic Stress Disorder Check List (PCL). In particular, patients with adverse childhood experiences exhibited a greater degree of relief related to anxiety and PTSD symptoms than those without adverse childhood experiences. Conclusion The present results demonstrated that the relatively short online imagery-based treatment program developed for this study had beneficial effects for patients with workplace-related PTSD.