Objective To investigate the effect of sarcopenia on postoperative complications in patients undergoing pancreaticoduodenectomy（PD）. Methods The data of 225 patients who underwent pancreaticoduodenectomy in the Nanjing Hospital Affiliated to Nanjing Medical University (Nanjing First Hospital) from March 2012 to February 2020 were retrospectively analyzed. The total area of the skeletal muscle was measured by CT images at the level of the third lumbar vertebra for the diagnosis of sarcopenia. The patients were divided into sarcopenia group and non-sarcopenia group. The clinical data and surgical complications were compared between the two groups to explore the relationship between sarcopenia and postoperative complications. Results Compared with the non-sarcopenia group, the patients in the sarcopenia group were older and had lower hemoglobin concentration, lower serum albumin concentration, and higher total bilirubin levels (P<0.05). The incidences of clinically relevant pancreatic fistula (grade B and C fistula), pulmonary infection, atelectasis and hypoxemia in the sarcopenia group were significantly higher than those in the non-sarcopenia group (P<0.05). The length of ICU stay and perioperative mortality in the sarcopenia group were significantly higher than those in the non-sarcopenia group (P<0.05). Multivariate analysis showed that sarcopenia, preoperative total bilirubin level, pancreatic duct diameter and pancreatic texture were independent risk factors for clinically relevant pancreatic fistula (P<0.05). Sarcopenia, intraoperative blood loss and postoperative abdominal infection were independent risk factors for pulmonary complications after PD (P<0.05). Conclusions Sarcopenia is an independent risk factor for increased incidence of clinically relevant pancreatic fistula and pulmonary complications after PD. Strengthening perioperative nutritional therapy and rehabilitation exercise in patients with sarcopenia is of great significance to reduce postoperative complications of PD.