Background: Preterm human milk has advantages over preterm formula (PF), but it may compromise some functions after pasteurization. Objective: To explore the effects of preterm donor milk (DM) on growth, feeding tolerance, and severe morbidity in very-low-birth-weight infants. Method: This was a single-center, prospective cohort study that included 304 preterm infants weighing <1,500 g or of gestational age <32 weeks. If the mother’s own milk was insufficient, the parents decided to use PF (n = 155) or DM (n = 149). The two groups were uniformly managed according to the standard NICU protocol. Growth parameters, feeding tolerance, and severe morbidity such as necrotizing enterocolitis, were compared between the two groups. Results: The daily weight gain and weekly head growth in the DM group were not different from those in the PF group (P > 0.05). Feeding intolerance in the DM group was significantly lower than that in PF group (P < 0.05), and parenteral nutrition time and hospitalization time were also shorter than that in the PF group (P < 0.05). Moreover, the incidence of necrotizing enterocolitis and sepsis was also significantly lower in the DM group (P < 0.05). Conclusion: The study indicated that preterm DM does not affect the growth of very-low-birth-weight infants. Further, it significantly reduces feeding intolerance, helps achieve full enteral feeding early, and has protective effects against necrotizing enterocolitis and sepsis. Thus, compared with formula, preterm DM can lower the rate of infection in preterm infants and is worthy of promotion.