Aim To investigate whether the interaction between necroptosis (Nec) and reactive oxygen species (ROS) mediates high glucose (HG)-induced injury in H9c2 cardiac cells. Methods The expression level of RIP3 protein (an important index that reflects Nec) was determined by Western blot assay. The cell viability was measured by cell counting kit-8 (CCK-8) assay. Mitochondrial membrane potential (MMP) was examined by Rhodamine 123(Rh 123)staining followed by photofluorography. The intracellular levels of ROS were detected by 2’, 7’-dichlorfluorescein-diacetate (DCFH-DA) staining followed by photofluorography. Apoptotic cells were evaluated by the nuclear morphology observed with Hoechst 33258 staining followed by photofluorography. Results After the H9c2 cells were treated with 35 mmol/L glucose (HG) for 0～24 h, respectively, the expression levels of RIP3 protein were significantly increased at 3 h, 6 h, 9 h, 12 h and 24 h, reaching the maximum level at 24 h. Cotreatment of the cells with necrostatin-1 (Nec-1, a specific inhibitor of Nec) considerably blocked the up-regulation of RIP3 expression level induced by HG. Moreover, cotreatment with Nec-1 obviously inhibited HG-induced injuries (including cytotoxicity, mitochondrial damage and oxidative stress), leading to an increase in the cell viability, decreases in a loss of MMP and ROS generation. On the other hand, pretreatment of the cells with 1000 μm N-acetyl-L-cysteine (NAC, a scavenger of ROS) for 60 min before HG exposure obviously reduced the HG-induced increase in the expression of RIP3. In addition, pretreatment of the cells with NAC dramatically alleviated the HG-induced apoptosis and cytotoxicity. Conclusion The interaction between Nec and ROS mediates HG-induced injury in H9c2 cardiac cells.