The purpose of this study is to identify the determinant factors of golf instructors\' performance in order to provide date necessary for improving the effectiveness of golf instruction. To achieve this purpose a qualitative case study was conducted using 4 subjects. In -depth interviews were the method of data collection. The collected date were encoded and sub-classified according to the research method suggested by Yang(2000) for cultural studies. The validity and reliability of this study was evaluated by carious methods such as triangulation. peer debriefing. member checks etc. As a result the determinant factors of golf instructors performance was classified into various factors. the major results of the analyses on this study are as follows. Intelligence moral character and basic body fitness are important dispositions for high performing athletes. Experience systematical organization and balanced tracing of skill. fitness, and mentality are important factors of effective teaching methods . It is important to note that golf is static concentration must be great. studies on how to adjust to one\'s environment are needed and athletes senses be separately trained. Knowledge necessary to instructors include English. physiology biomechanics psychology and computer Information and pinion exchange among instructors as well as observation from various angles level up the quality of instruction . The ideal instructor is said to have character theory and practive. The instructors performnace factors are the same with regard to fitness training. basic equipment . positive thinking and instruction emphasis on mental aspects and trust. Instructors need to develop an relizable professional teaching method though exploratoy and critical self-reflection Also, a comprehensive ans detailed study on the factors that contrivute to inprovement in athletes performance in competitions is needed.