Blood transfusion is a hazardous medical treatment and safety in blood transfusion is imperative to patient safety. Although there is a complete standard procedure of blood transfusion, some adverse cases are still occurred caused by human error. The mechanism of monitoring and informing during the process of blood transfusion are all critical stages to ensure the safe transfusion. The purpose of this research is to develop a computer-aid system which could automatically inform the department which needs blood bags by using barcode to check whether the blood bags is for the right patient. The system we developed is already practiced at blood transfusion in one Medical Center in southern Taiwan, and we expect to leverage computerize procedures to help identification and authentication during the whole transfusion for ensuring transfusion safety, reducing the probability of medical errors, and providing high quality medical care.