Objective To investigate the protective effect of naringenin on hypoxia-injured myocardial cells. Methods A hypoxia-injured myocardial cell model was established with rat myocardial cell line H9c2 cells and identified by lactate dehydrogenase (LDH) cytotoxicity test kit. The experiment was divided into 5 groups: control group, model group, and naringenin low-, medium- and high-dose groups (20, 40 and 80 μmol/L). Cell proliferation inhibition rate was detected by cell counting kit 8; cell hypertrophy was detected by indirect immunofluorescence; cell apoptosis was detected by flow cytometry; the protein expression of apoptosis-related proteins B-cell lymphoma 2 (Bcl-2), Bcl-2 associated X protein (Bax) and caspase 3 was detected by Western blotting; and the mRNA expression of vascular endothelial growth factor (VEGF), NK2 homeobox 5 (Nkx2.5) and alpha-smooth muscle actin (α-SMA) in H9c2 cells was detected by qRT-PCR. Results Compared with the control group, the activity of LDH in cell supernatant of the model group was significantly increased (P<0.01), indicating that the hypoxia-injured myocardial cell model was successfully constructed. Compared with the model group, the inhibition rate of cell proliferation was significantly decreased in each dose group of naringenin (P<0.05, P<0.01); the hypertrophy of H9c2 cells in each dose group of naringenin was significantly alleviated (P<0.05, P<0.01); and the proportion of apoptotic cells was significantly decreased in the medium- and high-dose naringenin groups (both P<0.01). Compared with the model group, the expression levels of apoptotic proteins caspase 3 and Bax in each dose group of naringenin were significantly decreased, while the expression levels of apoptosis inhibition-related protein Bcl-2 were significantly increased (P<0.05, P<0.01). Compared with the model group, the mRNA expression level of Nkx2.5 in high-dose naringenin group was significantly increased (P<0.01), the mRNA expression levels of VEGF were significantly increased in medium- and high-dose naringenin groups (P<0.05, P<0.01), and the mRNA expression levels of α-SMA were significantly decreased in each dose group of naringenin (all P<0.01). Conclusion Naringenin has a protective effect on hypoxia-injured myocardial cells of rats.