Objective To investigate before extracorporeal circulation and after HMGB₁, CK, CK-MB, LDH, LD₁, AST levels and significance in serum of patients. Methods 57 cases before extracorporeal circulation surgery and after, the levels of HMGB₁ were detected by ELISA,while the levels of CK and CK-MB and LDH and LD₁ and AST were detected by using conventional methods of clinical. Difference of HMGB₁ and CK, CK-MB, LDH, LD₁ and AST levels were compared. The relationship were been analyzed on the patients before extracorporeal circulation surgery and after. Results In extracorporeal circulation surgery, HMGB₁, CK, CK-MB, LDH, LD₁, AST levels after surgery in 0.5 hours, 24 hours, 48 hours,72 hours were higher than before surgery (P<0.05); HMGB₁, CK, CK-MB, LD₁, AST levels peaked at 24 hours aftersurgery, LDH levels was peaked at 48 hours after surgery, and then gradually declined. Extracorporeal circulation blocking was prolonged, the levels of HMGB₁ and CK and CK-MB and LDH and LD₁ and AST were elevated. After extracorporeal circulation surgery in serum the levels of HMGB₁ expression and CK,CK-MB,LDH, AST indicators showed a positive correlation(P<0.05). Conclusion The levels of HMGB₁, CK, CK-MB, LDH, LD₁ and AST were elevated after extracorporeal circulation surgery. HMGB₁ was involved in myocardial ischemia and reperfusion injury.