Abstract: With the technology of PCR, the completed ..-hemolysin gene AHL316HEM was obtained from the amplification of an Aeromonas hydrophila strain ML316 ( isolated from diseased Anguilla anguilla ) . The gene was cloned into pGEM-T Easy Vector. After analysis, the gene was inserted into pcDNA3. 0 vector to construct the recombinant plasmid PDLH. The E . coli DH5..w ith PDLH could lead to obvious ..-hemolysis plaque in blood-Agar. The hemolysis activity of crude purif ied transformant.. s extracellular products( ECP) was 1. 28 .. 104HU..mg- 1. Furthermore, the transformant.. s ECP could be recognized by ant-i serum which was raised against original bacterial strain. The above results demonstrated that the ..-hemolysin gene of ML316 had been cloned and the recombinant plasmid PDLH could express the product with native bio logical function. The success of cloning and expressing the ..-hemolysin gene of A . hydrophila will speed up the development of DNA vaccine against A . hydrophila.