Abstract: Objective:To investigate the differences of the positive detection rate between different day-age,different blood group of mother-baby,and "direct antiglobulin test,indirect antiglobulin test and dilution test" of child in hemolytic disease of the newborn(HDN).Methods:The ABO and Rh(D) blood groups in mother-baby were identified using the micro-column gel agglutination assay.The direct antiglobulin test,indirect antiglobulin test and dilution test in children,and the irregular antibody in mother with negative Rh(D) were examined.The positive rates of the different day-age,blood group of mother-baby and "three tests" in detecting the hemolysis were analyzed.Results:Among 418 neonates with high bilirubin,186 cases were diagnosed as HDN,the total positive rate of which was 44.50%.Among 186 HDN children,the neonates ≤ 3 days old in 125 cases(49.21%),neonates > 3 days and ≤ 7 days in 38 cases(39.18%),and neonates > 7 days in 23 cases(34.33%) were identified,the difference of which was statistically significant(P<0.05).The blood group of mother-baby as O-A in 95 cases(66.90%) and O-B in 91 cases(57.96%) were found,the difference of which was not statistically significant(P>0.05).The positive rates of the direct antiglobulin test,indirect antiglobulin test and dilution test were 7.66%,31.82% and 44.50%,respectively.Conclusions:The most common type of HDN is ABO-HDN,the detection rate of neonates ≤ 3 days old is the highest,and the positive rate of dilution test is highest,which can be used as the directly diagnostic basis of HDN.