本研究的目的在於探討團體督導對碩士層級準諮商師團體領導能力的督導效果，並進一步了解督導效果因何而來。研究參與者為八位輔導與諮商學系碩士層級的準諮商師。於督導進行前後分別評估受督導者的起點行為及其改變情形。為了充分了解團體督導效果與其來源，同時運用量化與質性兩種評估方法。在量化評估方面，採準實驗法前後測單組設計，以「團體諮商領導能力評量表」作為評量工具，以了解團體督導的效果；在質性資料方面，則是分析受督導者的督導過程作業單與其接受訪談的質性資料，從受督導者觀點了解團體督導如何對其團體諮商領導能力有所助益。 研究結果顯示準諮商師經過實際團體的帶領、團體督導等經驗結束後，在理論基礎、團體過程的領導技巧與整體領導能力各項上後測分數顯著高於前測，表示經過六次團體督導後，準諮商師團體諮商領導能力有長足的進步。而在心理與行為特質、團體進行前準備技巧與團體諮商專業倫理行為方面則未達顯著差異。經由分析受督導者作業與訪談資料，受督導者表示督導過程中來自督導者的督導、解說與示範帶領團體的相關技巧、鼓勵受督導者彼此討論、相互觀摩與學習，均對其團體領導能力有相當的助益。 本研究並根據結果與限制，提出對諮商教育及後續研究的若干建議。

The purpose of this study is to investigate the supervision efficacy on the group counseling competence of 8 counselor trainees at the master level in group supervision and to get further understanding of the causes and effects. We adopt both quantitative and qualitative methods for the assessments. For quantitative assessment, we adopt the One-Group Pre/Post Test Design to assess the supervising effects in terms of "An inventory of Group leader's Counseling competence" as a tool. For qualitative assessment, we analyze the data on the supervising process and the interview with the supervisees. Our studies reveal the fact that the trainees' scores of pro-tests are higher than those of pre-tests with respect to the subscales of the theoretical background, the leading skills of ongoing group counseling, and the overall group counseling competence after six supervisory group sessions. However, there appears no substantial variation between the pre-and post tests for the trainees' scores in the inventory of psychology and behavior characteristics, the pre-group pre­paratory skills, and the ethics. According to the qualitative data, the trainees point out that there are several ways to get advantages.