Aim To investigate the protective effects of astragaloside Ⅳ on high glucose induced cardiomyocyte hypertrophy in neonatal rats. Methods Myocardial cells of neonatal rats were cultured in vitro,the hypertrophic myocytes were induced by 25 mmol/L high glucose(HG).Cultured neonatal rats' cardiomyocytes were divided into normal group,HG group,HG+16 μmol/L astragaloside Ⅳ,HG+32 μmol/L astragaloside Ⅳ,HG+64 μmol/L astragaloside Ⅳ,48 h later,total protein content was assayed by Lowry method.The cardiomyocyte volume was measured by computer photogragh analysis system.The cardiomyocyte viability was analysed by MTT assay.i transient was measured by Till image system and by cell-loading Fura-2/AM. Results Compared with normal control group,HG increased the total protein content,cardiomyocoytes size,i transient by 35.7%,81.3%,62.5% and decreased the cardiomyocyte viability by 36.1%.Compared with HG group,astragaloside Ⅳ 16 μmol/L reduced the total protein content,cardiomyocoytes size,i transient by 20.3%,10.6%,8.0% and cardiomyocyte viability was inceased by 20.0%.There was dose-dependent relationship. Conclusion astragaloside Ⅳ could protect cardiomyocyte hypertrophy in glucose-induced rats.