Abstract: In the present study, the cDNA sequence of Hyriopsis cumingii HSP70 (HcHSP70) was cloned by 3'rapid amplification of cDNA ends methods (3'-RACE) based on a long chain sequence of HcHSP70 and it was determined by high flux sequencing for transcriptome of H. cumingii blood cells, and its expression in the different tissues was detected with quantitative real time polymerase chain reaction (qRT-PCR). Results showed that the full-length of HcHSP70 cDNA was 2298 bp long including a 1974 bp open reading frame (ORF) encoding a polypeptide of 657 amino acids that estimated molecular mass of 71.6 Ku and an isoelectric point of 5.67. Sequence comparison indicated that HcHSP70 shares the highest identity (91%) with HSP70 of Tegillarca granosa and Crassostrea gigas. HcHSP70 mRNA expressed in all 5 detected tissues (hepatopancreas, gonad, gill, mantle, muscle) with the highest expression in hepatopancreas. Both mRNA and protein level of HcHSP70 in gill significantly up-regulated at 37℃ and rapidly reduced to normal level under 40℃.