More and more researches suggest that, skeletal muscle as a power organ has powerful endocrine function. The cytokines or peptides secreted and released by skeletal muscle are called myokine. So far, hundreds of muscle factors have been discovered. These myokines exert biological effects through autocrine, paracrine or endocrine forms, which have important regulatory effects on skeletal muscle signal transduction and peripheral tissue and organ metabolism. Myokine provides a molecular link between muscle and other tissues and organs, and plays an important role in cell communication. By following the latest research progress, this article elaborates the characteristics and biological functions of the major myokines that have been identified according to their effects.