The purpose of this study was to analyze the effect of musical activities in the forest on young children’s nature-friendly attitude, character, and musical creativity. In addition, through this, this study attempted to explore the possibility of applying the experiential music activity based on the natural elements of the forest, and seek for a way of enhancing the educational effects of musical activities as a variable of the age composition of the group. For experimental treatment, 75 young children aged 4 and 5 in kindergarten C, in W city were classified into the experimental group, comparison group, and the control group. The mixed-age group musical activities in the forest were applied to the experimental group, and the musical activities in the forest of the same age group were applied to the comparison group. Also, theme-oriented music activities based on the Nuri curriculum were applied to the control group in the classroom environment. In the results of this study, the musical activities in the forest were found to have positive effects on promoting the development of nature-friendly attitudes and character and musical creativity of young children, and the effect of the musical activities in the forest for the mixed-age group were found to be more effective than that of the musical activities in the forests for the same age group.