5'-AMP-activated protein kinase (AMPK) plays a central role as the intracellular energy sensor, and regulates various cellular metabolic pathways. Both exercise and muscle contraction, which result in the elevation of the ratio of AMP and ATP, cause the conformation change and allosteric regulation of AMPK molecule; then AMPK can be activated obviously by the upstream regulator LKB1 (AMPKK). After AMPK activated, AMPK is able to phosphorylate eNOS-NO-cGMP-PKG and p38MAPK signaling systems to induce GLUT4 containing vesicles translocation and activation, which enhance skeletal muscle glucose uptake. Moreover, exercise training-induced physiological adaptations might be mediated by AMPK signaling. It has been shown that repeated AMPK activation elevates the gene and protein level of CaMK-IV and PGC-1α, then initiates several downstream gene transcription factors activation and expression; simultaneously, AMPK also causes eNOS-NO signaling activation. It thus appears that exercise training induces muscle glycogen storage, angiogenesis, fiber type transformation, GLUT4 content, and mitochondrial biogenesis though the above AMPK-activated intracellular pathways.