Tripartite　motif　8　(TRIM8)　is　a　member　of　the　TRIM　protein　family　that　has　been　found　to　be　implicated　in　cardiovascular　disease.　However,　the　role　of　TRIM8　in　myocardial　ischemia/reperfusion　(I/R)　has　not　been　investigated.　We　aimed　to　explore　the　effect　of　TRIM8　on　cardiomyocyte　H9c2　cells　exposed　to　hypoxia/reoxygenation　(H/R).　We　found　that　TRIM8　expression　was　markedly　upregulated　in　H9c2　cells　after　stimulation　with　H/R.　Gain-　and　loss-of-function　assays　proved　that　TRIM8　knockdown　improved　cell　viability　of　H/R-stimulated　H9c2　cells.　In　addition,　TRIM8　knockdown　suppressed　reactive　oxygen　species　production　and　elevated　the　levels　of　superoxide　dismutase　and　glutathione　peroxidase.　Knockdown　of　TRIM8　suppressed　the　caspase-3　activity,　as　well　as　caused　significant　increase　in　bcl-2　expression　and　decrease　in　bax　expression.　Furthermore,　TRIM8　overexpression　exhibited　apposite　effects　with　knockdown　of　TRIM8.　Finally,　knockdown　of　TRIM8　enhanced　the　activation　of　PI3K/Akt　signaling　pathway　in　H/R-stimulated　H9c2　cells.　Inhibition　of　PI3K/Akt　by　LY294002　reversed　the　effects　of　TRIM8　knockdown　on　cell　viability,　oxidative　stress,　and　apoptosis　of　H9c2　cells.　These　present　findings　defined　TRIM8　as　a　therapeutic　target　for　attenuating　and　preventing　myocardial　I/R　injury.