In some cases, hematopoietic stem celltransplants (HSCT) show differences in the D antigen. In previous studies, there have been few cases of de novo anti-D alloimmunization, and even rarer cases of serious side effects or the outcomes. De novo anti-D alloimmunization has been reported to occur more frequently in minor D mismatch than in major D mismatch. For the RhD type of blood components, RhD-negative type is recommended in transfusion in RhD mismatch HSCT without anti-D in donors and recipients. But in situations of insufficient RhD-negative blood supply, this study suggests that the RhD type of blood components depends on the patients’ RhD type before transplantation, and it depends on the donors’ RhD type after transplantation, and an RhD-positive platelet transfusion may be available.