The purpose of this study was to examine the effectiveness of the forest healing program for improving the mental health of urban elderly people. Most participants were over 70 years old (87%) among total participants (46 people). The period was from May 5, 2015 to September, 4, 2015. During the experiment, research was stopped for one month due to the spread of Mers. The 46 subjects who were over 60 years old were divided into 4 groups by the number of participation (0, 4, 8, 12 times). Psychiatric tests and blood melatonin concentration test were performed before and after the experiment and the mean difference was determined by the corresponding sample t-test. Differences between the groups were analysed by ANOVA analysis. The change of melatonin concentration was examined by enzyme immunoassay. According to the result of the psychiatric test, mental health of the aged people who did not participate in the forest healing program was worse than 16 weeks ago. People who participated 4 times also had worse mental health. 8 and 12 times participated people showed improved mental health which indicate the need of long-term forest healing for mental health. The result of melatonin test showed that blood melatonin did not increase in the elderly people who did not participate, whereas blood melatonin of the elderly who participated for 12 times showed an increase tendency. This result is similar with the previous study, which suggested that melatonin can be increased by activity of body stimulation or mood change. In conclusion, we can say that forest healing programs have a positive effect on the mental health of elderly people. However, this study had several limitations. There is a need for follow-up studies to study age and individual differences, and to identify differences between periods