Abstract: Objective To compare the effects of different doses of amino acids and fat emulsions in parenteral nutrition on the incidence of complications and prognosis in very low birth weight infants (VLBWI). Methods The clinical data of 328 VLBWI who received nutrition support therapy for at least 5 days starting in 72 h after birth during January 2005 to December 2014, were retrospectively analyzed. According to the dosage in parenteral nutrition, patients were divided into low-dose group and high-dose group. The incidence of complications and prognosis between two groups were compared. Results There were 204 cases in low-dose group and 124 cases in high-dose group. Compared with the low-dose group, the incidence of complications was lower in high-dose group during hospitalization and the incidence of intracranial hemorrhage was reduced most; the incidence of developmental retardation was lower at discharge; the overall incidence of metabolic complications of parenteral nutrition was higher, among which the incidence of high blood glucose, electrolyte disturbance and cholestasis were increased and the incidence of hypoglycemia was lower, and the differences were all statistically significant (P??0.05). Conclutsions VLBWI can tolerate early aggressive parenteral nutrition which can reduce the incidence of extrauterine growth retardation and premature complications.