Based on prior studies that a high level of psycho-social health of adolescents has a significant relationship with healthy eating habits and the promotion of personal physical activity, this study examines whether the Global Citizenship Education (GCE) has a positive effect on various psycho-social indicators of adolescents. For this purpose, this study performed repeated measurements by split-plot of the factors that can have an effect as mediator variables while controlling the experience of volunteer work and completion of courses related to service. The effect of GCE, the independent variable, was performed by within-subject analysis under controlling the mediator variables by comparison between before and after points of view. Through between-subject analysis, a significance test was attempted through comparative analysis of differences between the levels of specific factors. This study verified whether the within-subject factor or GCE, the treatment effect affects the psycho-social health regardless of the level of a specific variable (main effect) and whether there is an interaction effect between treatment factor and insertion factor. In addition, if sphericity assumption is not met, this study tried to analyze the within-subject effects through well-known Greenhouse-Geisser verification method. As a result, in terms of the analysis of the effects within the participants of GCE, the effects of participating in GCE were significant in self-efficacy (.001), stress management (.021), and rest (0.13). In addition, in relation to volunteering experience, the effects between the GCE participants showed a significant difference in all of the variables of self-efficacy (.046), stress management (.002), personal relations (.000), and health care (.045), which confirmed that GCE has a positive effect on the psycho-social health promotion indicators of adolescents.