The objective of this study was to investigate the effect of the balanced diet intake in amateur swimmer. 34 swimming lovers in swimming course voluntarily participated in this study, they were randomly assigned to control group and diet intervention group and 17 people each group. This study lasted for 4 weeks and 3 times per weeks. After collecting the data and then analyzing them, the findings indicated that there were extremely significant difference between control and diet intervention group, the diet intervention has a significant role in amateur swimmers, it can improve the sport performance and reduce the exercise fatigue. The author suggests that the dietary intake should be balanced, the excessive protein or high fat diet will damage to the energy supply system and cause excessive fatigue in sports performer.