The invention relates to a nucleotide specific to Aeromonas hydrophila O antigens and an application thereof. The nucleotide comprises: (1) at least one of nucleotides shown as SEQ ID NO:1 to 8; and (2) at least one of nucleotides being complementary with the nucleotides shown as SEQ ID NO:1 to 8. The nucleotides can be used for preparing a PCR (Polymerase Chain Reaction) kit for detecting Aeromonas hydrophila and a gene chip. The nucleotide specific to the Aeromonas hydrophila O antigens and the PCR kit and the gene chip including the nucleotide have high practicability. The PCR kit has the advantages of easiness and convenience in preparation, short detection period, high speed, high operability, easiness for industrial production, relatively low detection cost, high accuracy and high sensitivity.