Disaster relief volunteers must have certain psychological and cognitive characteristics. Therefore, the present study aimed to investigate the effectiveness of the training program on improving knowledge, functional skills, and attitude among disaster volunteers. A quasi-experimental study was conducted in 2023 in Iran, including an intervention and control group and follow-ups. Ninety health volunteers were randomly selected and divided into two groups of 45. The experimental group received the training program for an hour a week for three months. The control group received no intervention. The participants of both groups completed the disaster preparedness questionnaire at the pre-test, post-test, and one and three months after the intervention. Data was analyzed using SPSS "version 26" software in the methods section. The intervention effect were significant in increasing the volunteers' functional skills (F = 3.75), knowledge (F = 166.50), and attitude (F = 1.74), all in (p = 0.001). According to the results, this effect was stable over time for functional skills (F = 1.83) and knowledge (F = 18.04) all in (p < 0.05). Training programs can help improve skills, attitudes and knowledge in natural disaster volunteers. Researchers interested in the field of natural disaster relief, particularly health researchers, could consider further examining the aforementioned topics in their studies.