Objective: This article studied the effect of breast milk supplemented with human milk fortifier (HMF) on the early recovery of infants after congenital cardiac surgery.Methods: Infants undergoing congenital cardiac surgery were randomly divided into an intervention group (n = 27) and a control group (n = 27). Infants in the intervention group received HMF, and those in the control group were exclusively breastfed. The nutritional indicators at discharge, the postoperative recovery status, and nutritional-related complications were recorded.Results: Compared with the control group at the time of discharge, the weight and albumin and prealbumin levels of the intervention group were significantly increased (P < 0.05). The length of hospital stay of the intervention group was significantly reduced compared with that of the control group (P < 0.05). Although the length of ICU stay for the intervention group was shorter than that of the control group, the difference was not significant (P > 0.05). No significant difference in the incidence of postoperative nutrition-related complications was noted between the two groups (P > 0.05).Conclusion: Compared with breastfeeding alone, with HMF can improve postoperative weight gains, reduce the length of stay, and promote infants' early recovery after congenital cardiac surgery.