Although quality assessment is gaining increasing attention,there is still no consensus on how to define and grade postoperative complications.The absence of a defimition and a widely accepted ranking system to classify surgical complications has hampered proper interpretation of the surgical outcome.This study aimed to define and search the simple and reproducible classification of complications following hepatectomy based on two therapy-oriented severity grading system:Clavien-Dindo classification of surgical complications and Accordion severity grading of postoperative complications.Two classifications were tested in a cohort of 2008 patients who underwent elective liver surgery at our institution between January 1986 and December 2005.Univariate and multivariate analyses were performed to link respective complications with perioperative parameters,length of hospital stay and the quality of life.A total of 1716 (85.46％) patients did not develop any complication,while 292 (14.54％)patients had at least one complication.According to Clavien-Dindo classification of surgical complications system,grade Ⅰ complications occurred in 150 patients (7.47％),grade Ⅱ in 47 patients (2.34％),grade Ⅲa in 59 patients (2.94％),grade Ⅲb in 13 patients (0.65％),grade Ⅳa in 7 patients (0.35％),grade Ⅳb in 1 patient (0.05％),and grade Ⅴ in 15 patients (0.75％).According to Accordion severity grading of postoperative complications system,mild complications occurred in 160 patients (7.97％),moderate complications in 48 patients (2.39％),severe complications (invasive procedure/no general anesthesia) in 48 patients (2.39％),severe complications (invasive procedure under general anesthesia or single organ system failure) in 20 patients (1.00％),severe complications (organ system failure and invasive procedure under general anesthesia or multisystem organ failure) in 1 patient (0.05％),and mortality was 0.75％ (n=15).Complication severity of Clavien-Dindo system and Accordion system were all correlated with the length of hospital stay,the number of hepatic segments resected,the blood transfusion and the Hospital Anxiety and Depression Scale-Anxiety (HADS-A).The Clavien-Dindo classification system and Accordion classification system are the simple ways of reporting all complications following the liver surgery.