We report a case of a newborn baby who suffered from hemolytic disease of fetus and newborn (HDFN) caused by anti-Di a. The baby presented with worsening jaundice started at three hours after birth and was transferred to Dongguan Maternal and Child Health Care Hospital. The newborn's hemoglobin (Hb) was 82 and 76 g/L at five and nine hours after birth, and the total bilirubin (TBIL) was 243.2 and 309.8 μmol/L, respectively. Blood samples of the newborn and the parents were collected for HDFN immunohematology test twelve hours after birth. They showed that the newborn and the father's blood type was A and RhDCCee, while the mother was A and RhDCcee. Direct antiglobulin test (DAT) indicateda strong positive for the newborn and negative for the parents. The reaction of the reagent to red blood cells for antibody screening with the patient's plasma, red cells eluate, and the mother's plasma were all negative, but were positive with the father's red blood cells. The newborn was recovered after treating with phototherapy, intravenous immunoglobulins and urgent blood exchange (the exchanged blood was the same ABO and RhD blood type and cross-matched). The newborn's plasma and red cells eluate were collected before blood exchange, and the mother's plasma were used to assess the red blood cells reaction, and IgG anti-Di a was identified in each sample. Di a blood typing was positive for the newborn and the father, and negative for the mother. Therefore, the newborn was diagnosed as HDFN caused by anti-Di a.