The purpose of this study was to evaluate an influence of plasma oxidant and anti-oxidant enzyme activity, and changes of percent body fat following Eriobotrya japonica extract supplementation during acute exercise performance in elite trained athletes. Total 12 subjects were participated in this study and divided into 2 groups (control group(CTG); n=6, loquat supplement group(LSG); n=6). All subjects had no history of injuries for last 6 months. LSG took Eriobotrya japonica extract supplementation for 4 weeks. All data of this research was analyzed by SPSS/PC 18.0 and signficant level was p<.05. The results of this study were as follow; In dialdehyde(MDA) concentration, there was a significant difference between rest and recovery -30 min of pre-(p<.01) and post(after 4 weeks)(p<.05) tests in CTG. In LSG, there was a significant difference between in rest and recovery -30 min of pre test(p<.05). In superoxide dismutase(SOD), there was a significant difference between in rest and immediately after exercise and recovery -30 min of post test in LSG(p<.01). In catalase(CAT), there was a significant difference between in rest and recovery -30 min of post test in CTG(p<.01). In LSG, there was a significant difference between in rest and immediately after exercise and recovery -30 min of post test(p<.05). As results above, It was suggested that long-term Eriobotrya japonica extract supplementation in athletes limited plasma MDA product during acute exercise, and positive effect on the improvement of anti-oxidant enzyme activity.