Abstract: Objective To evaluate the perioperative nutritional status of patients with rectal cancer in different stages，and to provide evidence-based medical basis for timely nutritional intervention by clinicians. Methods A prospective study was conducted in 240 patients undergoing resection of rectal cancer from September 2016 to November 2018.BMI，grip strength and subjective global assessment of nutrition（SGA）and serum albumin（ALB）were used to evaluate the nutritional status of 240 patients undergoing resection of rectal cancer during perioperative period.It was estimated that the same nutritional measurements were used at admission and discharge，and patients were reevaluated one month after discharge. Results 〖JP2〗A total of 240 rectal cancer patients were enrolled in the study，171（71.3%）with locally early rectal cancer and 69（28.8%）with locally advanced rectal cancer.SGA assessed that 74（30.1%）and 122（50.8%）of the 240 patients were malnourished at admission and discharge respectively，and the nutritional status at discharge was significantly worse than that at admission（P<0.05）.Body weight and ALB deteriorated significantly during hospitalization，and the follow-up showed that they continued to deteriorate in the short term after discharge，the weight and ALB were（68.2±15.3）kg，（37.8±0.4）g/L at admission and（63.8±16.9）kg，（35.9±0.56）g/L at discharge，（62.4±17.5）kg，（32.5±3.7）g/L at follow-up（P<0.05）.In addition，the body weight，SGA score（≥4）and ALB level of patients with locally advanced rectal cancer at admission，discharge and one month after discharge were lower than those in locally advanced rectal cancer（P< 0.05）. Conclusion Most patients with rectal cancer have good nutritional status at admission，but the nutritional status will deteriorate during hospitalization and early discharge，especially in patients with locally advanced rectal cancer.

Key words: rectal cancer, perioperative period, nutritional assessment, subjective global assessment of nutrition