Objective To investigate the status quo and influencing factors of malnutrition in elderly inpatients in department of gastroenterology. Methods Clinical data of 466 elderly patients admitted to Qionghai People′s Hospital from January 2021 to January 2023 were retrospectively analyzed. They were divided into malnourished group and non-malnourished group according to mini-nutritional assessment (MNA). The incidence of malnutrition in patients with different diseases was compared. The baseline data of the two groups were compared, and the difference information was included in the unconditional logistic stepwise regression analysis to identify the influencing factors of malnutrition in elderly inpatients in the department of gastroenterology. Finally, receiver operating characteristic (ROC) curve was used to analyze the value of age and Barthel index (BI) score in predicting malnutrition in elderly inpatients. SPSS statistics 22.0 was used to process the data, and t andχ² tests were used to compare the data between groups according to the data type. Results The MNA scores of 466 elderly inpatients in the department of gastroenterology were (19.44±5.29) points, of which 104 (22.32%) were malnourished and 362 (77.68%) were well-nourished. Among them, the incidence of malnutrition was highest in patients in department of gastrointestinal bleeding. Among the 102 cases of gastrointestinal bleeding, 62 (60.78%) were found to have malnutrition. Age, BI score, number of chronic diseases, anxiety or depression, and personal monthly income were compared between malnourished group and non-malnourished group (P<0.05). Multivariate logistic regression analysis showed that age(OR=2.745,95%CI 1.241-6.072), number of chronic diseases(OR=1.137,95%CI 1.034-1.250), anxiety or depression(OR=1.449, 95%CI 1.018-2.062), personal monthly income (OR=4.243,95%CI 1.974-9.120) and BI score (OR=4.209,95%CI 1.339-13.231) were the influencing factors of malnutrition in elderly inpatients in department of gastroenterology. ROC curve analysis of age and BI score confirmed that it had a good predictive value for malnutrition in elderly inpatients in the department of gastroenterology, and the area under the curve was 0.787 and 0.812, respectively. Conclusion Elderly inpatients in the department of gastroenterology have a high incidence of malnutrition, and the incidence of malnutrition is affected by age, the number of chronic diseases, anxiety or depression, personal monthly income, BI score, and should be paid attention to in the subsequent treatment of such patients.