With advanced of age, production of reactive oxygen species increases in muscle tissues, which causes a continuous elevation of oxidative stress in the muscle. Such oxidative stress brings damage by oxidation of cell components such as lipids, proteins, and DNA. Growing evidences suggest that oxidative stress affects energy metabolism, protein degradation, and apoptosis in the muscle via transcriptional and posttranslation regulation of key proteins, which results in loss of muscle mass and metabolic dysfunction. On the other hand, regular exercise and proper nutrition containing some antioxidant can improve the muscle function by a reduction of excessive oxidative stress. This article describes the influence of oxidative stress on the progress of age-related muscle dysfunction and reviews the effect of countermeasures such as exercise and diet.