Abstract: OBJECTIVE To explore the risk factors for postoperative surgical site infection (SSI) in the patients undergoing intracardiac surgery under extracorporeal circulation and observe the levels of serum inflammatory markers. METHODS The clinical data were collected from 100 patients who received the intracardiac surgery under extracorporeal circulation in the hospital from May 2015 to Jan 2017. The enrolled patients were divided into the SSI group and the control group according to the status of SSI, with 50 cases in each group. The preoperative cardiac function, history of other diseases and perioperative condition were statistically analyzed, the levels of serum procalcitonin (PCT), WBC counts and C-reactive protein (CRP) were detected. The univariate analysis and multivariate analysis were performed for SSI after the clinical were processed for quantitative assignment. The levels of PCT, WBC and CRP were compared between the two groups of patients before the surgery and after the surgery for 1 and 3 days. RESULTS The extracorporeal circulation time and operation duration were significantly longer in the SSI group than in the control group, the dosage of blood products of the SSI group was significantly more than that of the control group, the postoperative 12-hour blood glucose level of the SSI group was significantly higher than that of the control group, and there were significant differences (P＜0.05 or P＜0.01). The result of univariate analysis indicated that the incidence of SSI was associated with left ventricular ejection fraction less than 50%, cardiac function NYHA no less than grade Ⅲ, diabetes mellitus, chronic obstructive pulmonary disease, time of extracorporeal circulation no less than 90 min, operation duration no less than 240 min, continuous suture of incisional subcutaneous layer, secondary thoracotomy for hemostasis, dosage of blood products more than 2.5L, postoperative hyperglycemia(fasting blood glucose no less than 140mg/dL) and ICU stay no less than 72 hours (P<0.05). The result of multivariate logistic regression analysis showed that the operation duration no less than 240min, continuous suture of incisional subcutaneous layer and postoperative hyperglycemia were the risk factors for the SSI. The levels of inflammatory markers of the SSI group were significantly higher than those of the control group after the surgery for 1 and 3 days (P<0.05). CONCLUSIONS The operation duration no less than 240min, continuous suture of incisional subcutaneous layer and postoperative hyperglycemia are the independent risk factors for the SSI in the patients undergoing intracardiac surgery under extracorporeal circulation. The levels of serum PCT, WBC and CRP of the patients with postoperative SSI are significantly elevated, which can be used for diagnosis of SSI.