Abstract: Objective:A retrospective study has been peformed to analyze the frequency and specificity of unexpected erythrocyte antibodies among blood donors in our center in past three years, to explore the significance of unexpected antibody screening for blood donors, and to provide a basis for pre-transfusion examination.Method:The micro-plate method and tube test were used to screen and identify unexpected antibodies in 196 311 blood donors.Result:A total of 296 unexpected antibodies were detected in 196 311 blood donors.The detection rate was 0.15%.The detection rate of unexpected antibodies in females(2.14%) was significantly higher than that in males(0.28%) in 1170 RhD-negative blood donors(P<0.05).312 cases of unexpected antibodies were detected (including 31 cases of 15 repeated blood donors),including 12 cases of ABO blood group system,10 cases of Rh blood type system,84 cases of MNS blood type system,110 cases of P blood type system,and 10 cases of Lewis blood type system.and 86 cases of nonspecific antibodies.Conclusion:In order to ensure the safety of clinical blood transfusion, it is necessary to screen the unexpected antibodies in blood donors. The selection of screening methods need further verification, in order to detect more clinically significant antibody.