The purpose of this study is to investigate the effect of chelerythrine on the hypertrophy of cardiomyocytes of neonatal rats induced by different glucose levels and its mechanism. Using cultured neonatal ventricular myocytes as a model, groups were divided as: control (5 mmol x L(-1)); high glucose level (10, 15, 20, and 25.5 mmol x L(-1)); high glucose level (25.5 mmol x L(-1)) add different concentrations of chelerythrine (1 and 8 micromol x L(-1)); and control glucose level (5 mmol x L(-1)) add different concentrations of chelerythrine (1 and 8 micromol x L(-1)). Different groups of cardiomyocytes after adding corresponding treat factors were cultured for 48 hours. Cardiomyocytes' diameters and protein level were measured and the expression of PKC-alpha, PKC-beta2, p-PKC-alpha, and p-PKC-beta2 were measured by Western blotting. Compared with control group, neonatal myocytes cultured in high glucose levels showed increased cellular volumes, protein level and expression of PKC-alpha, PKC-beta2, p-PKC-alpha, p-PKC-beta2. When chelerythrine was added, cellular volumes, protein level and expression of PKC-alpha, PKC-beta2, p-PKC-alpha, p-PKC-beta2 were significantly reduced. But in 1 micromol x L(-1) chelerythrine group, the expression of PKC-beta2 was not significantly reduced. The result suggested that chelerythrine can reverse the hypertrophy induced by different glucose levels on the cardiac myocytes, it may have protective effect against diabetic cardiomyopathy via PKC passageway.