Objective To identify a case of Para-Bombay phenotype and analyze it's molecular background.Methods Routine serological methods were used to identify the antigens on red cells and antibodies in serum,the weak antigens on red cells were detected by absorption and elution test.ABO substances were determined by agglutination inhibition test in saliva.FUT1 and FUT2 gene were sequenced with molecular methods.Results The para-Bombay was confirmed as Ah-secretion.Two of the three T repeats located at the nucleotides 880-882 were deleted.This deletion causes the shifting of the open-reading frame.The FUT2 genotype was Se357Se357.Conclusion Para-Bombay phenotype is rare.Homozygous genotype of FUT1 allele,hh(nt880-882de1TT)might be the cause of H-antigens deficiency..The wild type of FUT2 allele was consistent with the secretor status.