Objective: To explore the influencing factors of malnutrition in elderly patients with heart failure (HF) and the effects of early enteral nutrition on cardiac function, nutritional status and intestinal mucosal barrier function in patients with malnutrition. 180 elderly patients with HF who were treated in our hospital from February 2021 to April 2022 were selected as the research objects. After admission, the nutritional status of all patients was evaluated according to the short-form mini-nutritional assessment (MNA-SF). According to the MNA-SF score results, they were divided into malnutrition group (n=83) and normal nutrition group (n=97). Univariate and multivariate Logistic regression were used to analyze the risk factors of malnutrition in elderly patients with HF. The elderly patients with HF malnutrition were given early enteral nutrition intervention, and the changes situation of cardiac function, nutritional status and intestinal mucosal barrier function were observed before treatment and 1 week after treatment. There were no significant correlation between malnutrition in elderly patients with HF and gender, residence, drinking history, etiology, occupational category, glutamic-pyruvic transaminase, serum creatinine, systolic blood pressure (SBP) and diastolic blood pressure (DBP) (P>0.05), and were associated with age, medical insurance type, disease course, marital status, New York Heart Association (NYHA) classification, educational level, C-reactive protein (CRP), family per capita monthly income, B-type brain natriuretic peptide (BNP), smoking history, left ventricular ejection fraction (LVEF) (P<0.05). Logistic regression analysis showed that longer disease course, higher CRP, higher BNP, NYHA classification IV, older age and smoking history were risk factors for malnutrition in elderly patients with HF (P<0.05). 1 week after treatment, LVEF was increased in elderly patients with HF with malnutrition group, and BNP was decreased (P<0.05). 1 weekafter treatment, the levels of prealbumin (PA) and transferrin (TRF) in elderly patients with HF in the malnutrition group were increased (P<0.05). 1 week after treatment, D-lactic acid (D-LAC), diamine oxidase (DAO) and intestinal fatty acid binding protein (IFABP) in elderly patients with HF in the malnutrition group were decreased (P<0.05). Malnutrition in elderly patients with HF is affected by the disease course, CRP, BNP, NYHA classification, age, smoking history and other factors. Early enteral nutrition for elderly patients with HF malnutrition is helpful to improve their cardiac function, nutritional status and intestinal mucosal barrier function. [ABSTRACT FROM AUTHOR]