Adverse reactions to blood transfusion are mainly divided into two types of adverse reactions, early adverse reactions and late adverse reactions. Early adverse reactions are roughly related to two factors, the first is reactions related to the quality of blood input, and there are four types of reactions, such as fever, allergy, hemolysis and bacterial contamination. The second is related to the large amount of rapid blood transfusion, with heart failure, tendency to bleed out and acid-base balance imbalance. The main late complications are hepatitis B, hepatitis C, malaria, syphilis, and AIDS.