Objective To investigate the influence of diabetes on the early complications after pancreaticoduodenectomy in patients with pancreatic cancer,and to provide reference for clinical diagnosis and treatment.Methods A total of 179 patients with pancreatic cancer confirmed by pathology underwent pancreaticoduodenectomy were divided into 81 cases of diabetes group and 98 cases of non-diabetes group according to the level of blood sugar.The fast blood glucose of patients in diabetes group were controlled at 5.6-11.2 mmol/L before surgery,the clinical and pathological data,surgery-related complications and systemic complications of two groups were compared.Results Of 179 patients,5 patients (2.79％) died of severe infection combined with cardiac and respiratory failure.Firm pancreatic texture occurred more in diabetes group than that in non-diabetes group(79.0％ vs 42.9％,x2 =13.62,P＜0.01),but no statistically significant difference in duration of operation,total bleeding,length of stay in hospital,diameter of pancreatic duct,tumor size,pathological pattern,whether reserved pylorus and methods of anastomosis between the two groups (P ＞0.05).There was no statistically significant difference in the incidence of pancreatic fistula,delayed gastric emptying,hemorrhage and infection between diabetes group and non-diabetes group (P ＞ 0.05),but the incidence of respiratory failure (4.9％ (4/81)),cardiac failure (9.9％ (8/81)) and renal failure (1.2％ (1/81)) in diabetes group were significantly higher than that in non-diabetes group (2.0％ (2/98),3.1％ (3/98),0(0/98);P=0.031,0.014,0.007).The incidence of pancreatic fistula was 26.3％ (47/179),and that of patients combined with diabetes (38.3％ (18/47)) and firm pancreatic texture (40.4％ (19/47)) were statistically lower than patients without diabetes and soft pancreatic texture (x2 =8.53,P ＜ 0.05;x2 =11.20,P＜0.01).Conclusion Pancreatic cancer has a big risk in pancreaticoduodenectomy,and those with diabetes would not increase the risk of pancreatic fistula,delayed gastric emptying,hemorrhage and infection when blood glucose is well controlled before surgery,but it has severe impact on systemic complications,so the perioperative blood glucose should be well controlled.