The purpose of this study is to identify the ego state and life position characteristics of some soldiers in a military unit and to find the effects of ego-state and life position on military service adaptation. To this end, data was collected from 307 army soldiers in a military unit. Then, descriptive statistics, correlation analysis, One-way ANOVA, and multiple linear regression analysis were performed using the SPSS 18.0 program. The research results are as follows. First, the ego state of the study participants was the Mountain Pattern, with NP as the highest point. Second, the life position of the study participants was found to be a type of ‘I’m OK․You’re OK’. Third, it was found that the level of military service adaptation of ‘I’m OK․You’re OK’, ‘I’m OK․You’re not OK’ and ‘I’m not OK․You’re OK’ was higher than that of ‘I’m not OK․You’re not OK’. Fourth, it was found that NP and ‘You’re OK’ had a positive effect on military service adaptation, respectively. Based on this study, It requires specific interventions which make soldiers avoid ‘I’m not OK․You’re not OK’ and activate both ‘NP’ and ‘You’re OK’ for their better adaptations while serving in the military.