To analyze the serological features and related blood group genes of a donor with A subtype of the ABO blood type.The ABO blood group of the sample was determined, in addition with the activity of blood group glycosyltransferase and blood group secretory substances. Sanger sequencing was adopted to analyze the genotype of the blood group.The proband was identified as A subtype (non-secretory type), with no detectable activities of a 1, 3-N-acetylgalactosyltransferase. DNA sequencing has identified a number of mutations including nt.261del/G and 297A/A of exon 6, and nt.467C/T, 806T/C and 1009A/G of exon 7. Clone sequencing has confirmed that the nt.806T>C exists at one allele and was a novel mutation. The proband genotype was A205/Onew (806T>C). The nt.806T>C of the exon 7 was confirmed to be a novel mutation, which was given a GenBank accession number KP341759. Family study showed that the genotype of the proband's father was Onew (806T>C)/O02, and that of his mother was A101/A205. The novel mutation of the proband has derived from his father.The reduced A antigenicity of the sample was due to the A205 subtype allele and the presence of a novel O allele.