Abstract: Objective: Explore confirm the effectiveness of the crossmatch blood experiment method,insure the controllability in crossmatch,so as to guarantee the safety in clinical transfusion.Method: To affirm the availability by comparison of experimental results form positive-negative-control and outcome from crossmatching.Positive control is by way of feedback from using mixed cell A and IgG anti-A serum in crossmatching of blood,while negative is by auto case-control.Result: The positive controls all remain in force in 516 samples of the adopted contrast in crossmatching between 2009-2011.Invalidation exists in 5 negative samples,including 2 samples are caused by using heparin during therapy,1 sample by hemolytic diseases of newborn,the other 2 are autoimmune hemolytic anemia.When changed to other negative-control,the invalid experiments of auto-case control from the 5 samples turn to valid indeed.No blood transfusion accident has happened of these 516 samples.Conclusion: It can eliminate error in experiments and enhance safety in clinical transfusion through the way of validity affirmation and quality control when adopting results form positive-negative-control in clinical crossmatching.