Sarcopenia and osteoporosis are two common metabolic diseases among the elderly population. Studies have found that there was a mutually reinforcing correlation in the process of their onset. Epidemiological research indicated that the incidence rates of sarcopenia and osteoporosis were positively correlated. Genetic studies have discovered genes that could simultaneously control low bone density and low muscle mass. Cell biology research has found that there were cytokines that act on both muscle cells and bone cells, and changes in their content could directly cause a decrease in muscle mass and bone density. Risk factor studies have found that there were common risk factors with a relatively clear mechanism that could cause the simultaneous onset of sarcopenia and osteoporosis. However, comprehensive high-level evidence demonstrating the mutual promotion of sarcopenia and osteoporosis during their onset was not yet complete, and the research on mechanism of their co-occurrence was not yet perfect, which has hindered the development of drugs for treating these diseases. Therefore, timely diagnosis of one of these diseases and control of common risk factors are effective methods for preventing and treating the co-occurrence of sarcopenia and osteoporosis.