Objective To study the influence of critical thinking training for nurses on transfusion security in emergency patients. Methods The nurses from the emergency department and outpatient department were trained with critical thinking.The incidence of transfusion safety flaws before training was compared to that after training. Results The total incidence of transfusion safety flaws after training was 10.0%, significantly lower than 35.8% before training(χ2=164.8, P<0.001).Conclusion The training of nurses' critical thinking may not only improve the comprehensive quality of nurses, but ensure the safety of transfusion.