The decline in skeletal muscle mass and function with age is referred as sarcopenia. It is characterized by the muscle fiber's quality, strength, muscle endurance and metabolic ability decreasing as well as the fat and connective tissue growing. Previous studies have shown that sarcopenia in itself features decreased number and cross-sectional area of muscle fibers and the net degradation of protein, which results from the joint effects of multiple factors such as the exacerbation of inflammation, oxidative stress injury, mitochondrial dysfunction, abnormal autophagy and dysregulation of muscle quality regulatory factors. In this review, we systematically displayed the molecular mechanism of sarcopenia, which will be helpful to deepen our understanding of sarcopenia and provide potential targets for the prevention and treatment of sarcopenia.