In order to amplify the Hsp70 gene of Marsupenaeus japonicus and study the features of the sequence,we designed a pair of primers according to the Hsp70 cDNA sequence of Fenneropenaeus chinensis(GeneBank accession No.AY748350) and the partial sequence of Marsupenaeus japonicus(GeneBank accession No.DQ663761),then used the RT-PCR program to amplify the complete Hsp70 gene.Total RNA was isolated using Trizol Reagent according to the manufactures instructions.The first strand cDNA was synthesized using reverse transcriptase Superscript.The polymerase chain reaction(PCR) was performed by the two-step method and the product was cloned to pMD-18 vector and sequenced.The sequence of cDNA,which was 1992bp in size,analyzed with software DNAstar,has a 1959bp open reading frame(ORF),encoding 652 amino acids with an ATPase domain of 386 amino acids,the substrate peptide binding domain of 60 amino acids and a C-terminus domain of 112 amino acids.The ORF of the Hsp70 gene sequence of Marsupenaeus japonicus has 94.5%,94.2% and 94.2% identity with the Hsp70 cDNA sequence of Litopenaeus vannamei,Penaeus monodon,and Fenneropenaeus chinensis,respectively.Under the alignment of Hsp70 amino acids deduced from DNA sequences,there is 99.5%,99.4% and 99.4% identity with Litopenaeus vannamei,Penaeus monodon,and Fenneropenaeus chinensis,respectively.A complete coding sequence(CDS) of Hsp70 gene was successfully amplified from M.japonicus.