Background Nurses require continuing education and training to maintain comprehensive and cooperative relationships with the survivors of disasters, understand their environment, and secure their safety. Method The aim of this study was to develop and test a psychological first aid nursing simulation that involved a standardized patient admitted to the emergency department after an earthquake. A nonrandomized feasibility trial was applied to test the effects of the program. The effects of the simulation were measured according to the participants' psychological first aid knowledge, performance competence, and self-efficacy. Data were analyzed using descriptive, difference, and correlation analyses. Results A total of 24 emergency nurses participated in this study. The results showed significant differences in psychological first aid knowledge, performance competence, and self-efficacy between the experimental group and the control group. Conclusion The psychological first aid training program used in this study was effective in improving nurses' psychological first aid knowledge, performance competence, and self-efficacy. [J Contin Educ Nurs. 2022;53(3):131-136.].