Abstract: Objective：To study the serological and molecular biological characteristics of 1 case of Bx subtype. Methods：Routine serological test was carried out to analyze 1 sample of blood typing discrepancy with positive and negative stereotypes, and further analysis was made on the 6 th and 7 th exon of ABO gene. Results：B antigen on red blood cells was significantly reduced, the anti AB response slightly enhanced, and the red blood cells could adsorb and elute anti B antibodies. Direct sequencing results showed that 261G deletion and 297A>G mutation were located at the 6 th exon. A total of 11 mutation sites including 526C>G, 646T>A, 657C>T, 681G>A, 703G>A, 769C>A, 771C>T, 803G>C, 905A>G, 930A>G and 1096G>A were located in the 7 th exon. Conclusions：The sample was identified as a rare Bx subtype, and the genotype was Bx02 and O02 hybrid.