Objective To analyze the nutritional status and its influencing factors of elderly trauma patients in perioperative period so as to provide scientific basis for early nutritional intervention and clinical diagnosis and treatment, promote clinical outcomes and prognosis, and improve their quality of life. Methods A total of 103 elderly trauma patients admitted in West China Hospital of Sichuan University from January 2021 to December 2021 were included in the study. The results of laboratory examinations and body composition data were recorded to describe the nutritional status of elderly trauma patients in multiple dimensions. According to the evaluation results of mini nutritional assessment-short form (MNA-SF), they were divided into nutritional risk group (n=46) and normal nutrition group (n=57). The nutritional status and the influencing factors were studied in the elderly trauma patients. SPSS statistics 19.0 was used to perform the statistical analysis. Student′s t test, rank sum test or Chi-square test was employed for intergroup comparison. Multivariate stepwise logistic regression for binary variables was performed to analyze influencing factors of nutritional status in elderly trauma patients. Results The results of MNA-SF showed there were 57 patients with good nutritional status, 39 with potential malnutrition, and 7 with malnutrition, with an incidence of nutritional risk of 44.66% (46/103). Elderly trauma patients also had nutritional problems such as insufficient energy intake, high blood glucose, high body fat, reduced skeletal muscle mass and low body protein level. Logistic regression analysis indicated that high body fat (OR=0.126,95%CI 0.022-0.707; P=0.019), low serum albumin level (OR=3.579,95%CI 1.365-9.388; P=0.010) and low skeletal muscle mass index (OR=4.757,95%CI 1.854-12.209; P=0.001) were significantly associated with nutritional risk in elderly trauma patients. The length of hospital stay was prolonged in the patients with nutritional risk (Z=-2.908, P=0.004) and those with low serum albumin level (Z=-3.511, P<0.001). Conclusion Elderly trauma patients had many nutritional problems and are at high nutritional risk, which is associated with the length of hospital stay. Monitoring of nutritional status should be carried out, especially in those with low body fat, serum albumin and skeletal muscle mass index. Timely nutritional support should be given to improve their nutritional status and prognosis.