Objective: The prevalence of metabolic syndrome and type 2 diabetes is increasing worldwide. Mitochondrial dysfunction is known to be involved in insulin resistance and obesity, researches have been increasing highly. Astragali Radix extract (ARE) or its main components have been shown to perform comparably to insulin by significantly reducing blood glucose levels in animalmodels however, the influence on mitochondrial dysfunction are not well understood. Methods: ARE (0.2, 0.5 and 1.0 mg/ml) or metformin (2.5 mM) were treated in C2C12 after 6day-differentiation. The expressions of adenosine monophosphate (AMP)-activated proteinkinase (AMPK) and phosphorylation AMPK, peroxisome proliferators-activated receptror γcoactivator 1α (PGC1α), nuclear respiratory factors 1 (NRF1), mitochondrial transcription factor(Tfam) and myosin heavy chain were detected with western blotting or polymerase chain reactionanalysis. The morphological changes were also investigated. Results: ARE dose dependently increased phosphorylation of AMPK and respectively activated mRNA expressions of PGC1α, NRF1 and Tfam which are mitochondrial biogenesis regulators. Furthermore, there were some morphologic differences of differentiated cells between ARE treatment and control. Conclusions: This study suggests that ARE has the potential to increase muscle mitochondrialfunction by activating AMPK and PGC1α.