Objective: To compare the clinical efficacy of early enteral ecoimmunonutrition (EIN) and conventional early enteral nutrition (EN) in patients with severe acute pancreatitis (SAP). Methods: Sixty-four consecutive SAP patients were randomly designated to observational group and control group, with 32 cases in each group. Patients in both groups received early EN support, while those in observational group were additionally supplemented with glutamine granules and triple vital bacteria composition. The case dropout, and nutrition status, inflammatory indexes and positive rate of bacterial DNA extraction in whole blood and plasma levels of diamine oxidase (DAO), D-lactate acidosis, endotoxin as well as the lactulose to mannitol ratio (L/M) in urine before and 9 d after of EN support were observed in the two groups. Results: There were 4 dropout cases in control group who were not able to follow the requirements of the nutritional support. In both groups on 9 d after EN support compared with the data before EN support, the levels of serum albumin, prealbumin and transferrin were increased; the levels of interleukin-2, interleukin-6 and tumor necrosis factor-α were decreased; the positive rate of bacterial DNA extraction and the plasma levels of DAO, D-lactate acidosis, endotoxin and L/M ratio were decreased, however, the changing amplitudes in all these parameters in observational group were greater than those in control group (all P<0.05). Conclusion: Rational early EIN is beneficial in improving the nutrition status, inhibiting inflammatory responses and maintaining intestinal barrier function in SAP patients, so it is recommended to be used.