Blood group O-positive means that a person’s blood type is O and also Rh-positive. This is the most comprehensive expression of blood type, because there are dozens of human blood type systems, but only two are widely used in clinical practice, one is the ABO blood type system, and the other is the Rh blood type system.The ABO blood type system is divided into four categories, including blood type A, blood type B, blood type O, and blood type AB, and the ABO blood type system is relatively well known to the general public, but most people do not understand the Rh blood type system very well.The Rh blood type system is divided into two categories according to the different antigens contained in the red cell membrane, which contain Doppler. The Rh blood group system is divided into two categories according to the antigens contained in the red blood cell membrane, those containing the D antigen are Rh-positive, and those not containing the D antigen are Rh-negative, so blood group O-positive means O blood in the ABO blood group system, and Rh-positive blood in the Rh blood group system.