This study was purposed to explore psychological change and regulation process during badminton competition. The data were conducted using group interviews and participation observations who 18 K college badminton players. The data were analyzed using open, axial, and selective coding based on grounded theory method (Strauss & Corbin, 1998). The results were as follows: Open coding results, 89 concepts, 44 subcategories, and 18 categories emerged as psychological change and regulation process during badminton competitions. Axial coding results, the categories are showed structural relationships such as performance, score, psychological momentum, the importance of competition, court environment, physical condition, competition strategy, psychological preparation, past experience, outcome expectation, psychological disturbance, psychological skills, game situation-changing strategy, support-seeking strategy, significant others' behavior, the opponents' behavior, psychological resilience, and maintenance psychological disturbance. Selective coding results, core category of this study was revealed to maintain psychological homeostasis. Environmental context during badminton competitions causes specific situations and events that evoke psychological disturbance. In turn, a player seeks mental and behavioral strategies to maintain psychological homeostasis. There is psychological homeostasis mechanism during badminton competitions for peak performance. Development of proper interest for psychological homeostasis will be improved through this research approach in sport psychology.
