The present invention relates to a Vibrio harveyi-specific binding Dscam of shrimps, a method for identification thereof and a use thereof. Primarily, Dscam cDNAs are prepared from V. harveyi-challenged shrimps. A database is established with various Dscam isoforms therein by means of numerous cloning and sequencing. After a phylogenetic analysis, a plurality of candidate Dscam isoforms is selected. Each recombinant protein of candidate Dscam isoforms is expressed through an expression system. Finally, the binding affinity between V. harveyi and each recombinant protein of candidate Dscam isoforms is measured to further selection of a V. harveyi-specific binding Dscam and the amino acid sequence thereof. Accordingly, the Dscam can be specifically binding to V. harveyi for eliminating or reducing V. harveyi.