The purpose of this study was to analyze the existing researchin a systematic way to evaluate the effect of music therapy on psychosocial adjustment and to present theoretical and practical basis for development and application of more effective therapeutic program. For this purpose, a meta-analysis was conducted on 52 domestic journals and theses that reported the effects of music therapy in the area of psychosocial adjustment. The results were as follows: First, the overall mean effect size was 0.51 with the fact that school adjustment and cultural adjustment showed a large effect size followed by other adjustments including family, military and job adjustment and adaptive behavior that showed a medium effect size. Second, in the age and characteristics of clients, middle and high school students disability/disease group showed the largest effect size. Third, in the types of interventional method, active techniques, single musical activity-centered protocol and the program with interdisciplinary theoretical basis showed bigger effect size than combined techniques, complex musical activities-centered protocol and the program with traditional theoretical basis. Forth, a larger effect size was showed in the case of setting a single goal, a total of 9 to 15 sessions, 50-60 minutes for each session. In conclusion, music therapy can be an effective intervention to improve psychosocial adjustment in various categories. At the same time, a variety of factors related to types and clients of adjustment, interventional methods, and characteristics of program can have a significant impact on therapeutic effects.