Abstract: This paper reported a very sensitive,precise and rapid method for detecting ABO blood groups.We used anti-A and anti-B McAb as the first antibodies and~(125)Ⅰ-labelled antl-mouse IgG the second anti- body.The sensitivity of this method could reach 1:5000 dilution,and the blind test of all samples were correct.These results showed that SPRIA should be practical used in identifying blood group antigens from bloodstain,saliva,semen,etc.