Background: The studies about the protective effect on the heart of single Atractylodes macrocephala rhizoma (AMR) herb and mechanisms have not been reported. Objective: The purpose of this study was to assess the effects of AMR on attenuating myocardial hypertrophy induced by isoproterenol (ISO) in mice. Materials and Methods: Mice were randomly divided into normal control group, ISO control group, ISO plus metoprolol (60 mg/kg) group, ISO plus AMR (2, 4, and 8 g/kg) groups, and AMR (4 g/kg) control group. The mice with myocardial hypertrophy were established by subcutaneous (s.c.) injection with ISO (2 mg/kg/d) and administered intragastrically with the corresponding drugs in the volume of 0.2 mL/10 g/d for 7 days. In the normal and AMR control groups, mice were injected (s.c.) with physiological saline (the solvent for ISO) and administered intragastrically with drinking water for 7 days. Results: Compared with the ISO-induced group, AMR significantly decreased heart weight index, left ventricular weight index, and average transverse area of cardiomyocytes, significantly increased the activity of total superoxide dismutase in serum and the level of the angiotensin II receptor type (AT) gene expression in myocardium and significantly decreased the contents of malondialdehyde, cyclic adenosine monophosphate , and aldosterone in serum and angiotensin II (Ang II) in myocardium. Conclusion: The ability of AMR to mitigate myocardial hypertrophy is partly associated with its anti-oxidative effect, restraining excessive secretion or activation of neuroendocrine factors, and the stronger upward effect on AT2gene expression than AT1.