Purpose: This study targeted female university students in their 20s and created an antioxidant improvement program with a health contract, one of the behavioral modification therapies, based on King’s (1981) ‘goal attainment theory.’ The aim of this study is to investigate the effects of physiological indicators, eating habits, dietary attitudes, and health behaviors by conducting a walking exercise and anti-oxidation diet program with reinforcement therapy. Methods: This study had a nonequivalent control group pretestposttest design. There were a total of 50 participants, with 25 participants in the experimental group and 25 participants in the control group and the study period was 10 weeks. The antioxidant improvement program consisted of walking and antioxidant diet education with health contracts. Data analysis was statistically processed using the SPSS/WIN 24.0 program. Results: The program showed a high achievement rate by providing continuous motivation and positive reinforcement during the program, and it affected the eating habits, dietary attitudes, and health behavior. Besides, physiological variables, such as antioxidant indices and body composition showed positive changes. Conclusion: This study, based on the goal attainment theory, confirmed that antioxidant improvement program is an effective nursing intervention for continuous health promotion through interaction and exchange between healthy participants and researchers.