Abstract: OBJECTIVE To investigate the protective effects of Salidroside in H9c2 cardiomyocytes under oxidative stress and hyperglycemia. METHODS H9c2 cardiomyocytes were divided into five groups： ①the control group （the cells treated with normal glucose）；②the high glucose group （the cells treated with high glucose）； ③the H₂O₂ group （the cells treated with H₂O₂ for 2 hours）； ④the high glucose+H₂O₂ group （the cells treated with H₂O₂ and high glucose）； ⑤the high glucose+H₂O₂+Salidroside group（the cells treated with H₂O₂ and high glucose and salidroside）. Activity of H9c2 cardiomyocytes was detected by cell counting kit （CCK-8）.The rate of apoptotic cells were detected by flow cytometry.The expression of OPA1 and Drp1 protein in mitochondria was determined by Western blot.Mitochondria membrane potentials were measured by JC-1 kit. RESULTS ①Compared with the control groups，the expression of OPA1 cells decreased （P<0.01），the expression of Drp1 cells increased （P<0.01），accompanied by reduction in mitochondrial membrane potential and the rate of apoptotic cells were increased （P<0.05）in high glucose group；Compared with the control groups，the expression of OPA1 cells decreased （P<0.01），the expression of Drp1 cells increased（P<0.01），accompanied by reduction in mitochondrial membrane potential and the rate of apoptotic cells were increased（P<0.01）in H₂O₂ group and high glucose+ H₂O₂ group；②Compared with the high glucose+H₂O₂ group，the expression of OPA1 cells increased（P<0.01），the expression of Drp1 cells decreased（P<0.01），accompanied by increased mitochondrial membrane potential and the rate of apoptotic cells were decreased （P < 0.01） in salidroside+ high glucose+ H₂O₂ group. CONCLUSION ①Oxidative stress and hyperglycemia can inhibit the balance of mitochondrial dynamics of H9c2 cardiomyocytes， reduce the mitochondrial membrane potential， and increase the apoptosis of cardiomyocytes， so as to damage cardiomyocytes. ②Salidroside can alleviate injury under oxidative stress and hyperglycemia，reduce cardiomyocyte apoptosis and protect cell mitochondrial function， and its mechanism is related to increased expression of OPA1 and decreased expression of Drp1，to improve the mitochondrial dynamic balance， and the increase of mitochondrial membrane potential level. Salidroside has a protective effect on oxidative stress and hyperglycemia， which deserves further study.