Blood type A RH positive means that a person’s blood type is A in the ABO blood type system and RH positive in the RH blood type system. Because there are various blood systems in the human body, in clinical practice, the widely used ones are the ABO blood group system and the RH blood group system. In the ABO blood group system, human blood types are divided into A blood type, B blood type, AB blood type and O blood type. In the RH blood group system, the human blood group is divided into RH positive and RH negative, if the red blood cell membrane contains D antigen is RH positive, without D antigen is RH negative. RH blood group has a very important significance in clinical transfusion, because RH negative people can only receive RH negative blood, if the transfusion of RH positive blood, serious hemolytic reactions will occur, but RH positive people can receive RH-negative blood.