Type O blood is not a sign of low IQ. It is said that type O blood has lower IQ than other blood types. This statement has been circulated to this day, but science has proved that these statements are completely unscientific and are seriously contrary to the facts. This article will introduce the truth between O blood type and IQ from four aspects: genetics, brain, pathology and IQ cognition. Type O blood based on genetic basis. Type O blood does not have the genetic characteristics of blood types A and B, so it can only affect the health of the people it lives in.