OBJECTIVE： To observe the effects of Shenfu yixin decoction on reactive oxygen species （ROS） and energy metabolism in primary hypoxic cardiomyocytes. METHODS： After isolation， culture and identification， primary cardiomyocytes of neonatal SD rats were randomly divided into normal group， model group， positive control group （coenzyme Q10， 0.1 mmol/L） and Shenfu yixin decoction low-dose and high-dose groups （0.25， 0.5 mg/mL）. Except for normal group， other groups were cultured with 5％O2， 5％CO2 and 90％N2 for 6 h to induce hypoxic injury model. After 6 hours of hypoxia， ROS contents in cardiomyocytes and mitochondria of each group were detected by ROS probe and flow cytometry. Luciferase luminescence and Western blotting were used to detect ATP content and CK protein expression of each group. Transmission electron microscope was used to observe ultrastructure of cardiomyocytes in each group. RESULTS： Compared with normal group， the expression of ROS in primary hypoxic cardiomyocytes and mitochondria as well as the content of ROS were increased significantly， while the content of ATP and expression levels of CK protein were decreased significantly （P＜0.05）； there were swelling of endoplasmic reticulum and mitochondria， dissolution or even disappearance of mitochondrial ridge， obvious cardiomyocytes injury. Compared with model group， the expression of ROS in primary hypoxic cardiomyocytes and mitochondria of administration groups， the contents of ROS in primary hypoxic cardiomyocytes of positive control group and Shenfu yixin decoction high-dose group as well as the content of ROS in primary hypoxic cardiomyocytes mitochondria of administration groups were all decreased significantly， while ATP contents in primary hypoxic cardiomyocytes of positive control group and Shenfu yixin decoction high-dose group as well as expression levels of CK protein in primary hypoxic cardiomyocytes of administration groups were all increased significantly （P＜0.05）. The primary hypoxic cardiomyocytes injury was relieved significantly in positive control group and Shenfu yixin decoction high-dose group. CONCLUSIONS： Shenfu yixin decoction can improve primary hypoxic cardiomyocytes， down-regulate the expression of ROS in cardiomyocytes and mitochondria and also improve its energy metabolism.