Blood group B Rh-positive refers to the expression of antigen B on the surface of human red blood cell membranes and the expression of antigen D of the Rh blood group system, so it is called blood group B Rh-positive. The two commonly used blood group systems are the ABO blood group system and the Rh blood group system, the ABO blood group system is based on the expression of antigen A and antigen B on the surface of the red blood cell membrane to classify human blood groups into four blood groups. The classification of the Rh blood group system refers to the expression of the rhesus D principle on the surface of the red blood cell membrane as Rh-positive blood and the non-expression of the D principle as Rh-negative blood.