In this study, a hemocyanin cDNA named EcHc was cloned from the hepatopancreas of the ridgetail white prawn Exopalaemon carinicauda by reverse transcription PCR (RT PCR) and rapid amplification of cDNA end (RACE) methods. The full length cDNA of EcHc was 2 158 bp and had an open reading frame(ORF) of 1 992bp encoding 663 amino acids which contained a signal peptide sequence(1~15 amino acid residues). The predicted molecular weight of the mature peptide was 75.05kDa, and the theoretical pI was 569. The homology analysis of EcHc with other hemocyanin showed higher similarity with Macrobrachium nipponense (86%). Quantitative real time RT PCR analysis revealed that microbial challenge resulted in mRNA up regulation, up to 6h post injection of Vibrio anguillarum or white spot syndrome virus (WSSV). The results indicated that the EcHc plays important roles in the immune defense system of E. carinicauda.