Abstract: The heat shock transcription factor 1 (HSF1) is a regulatory factor widely present in eukaryotes and has many physiological functions in vivo. In order to explore the role and molecular mechanism of HSF1 in the process of high temperature tolerance, and further elaborate its physiological function, we cloned the HSF1 gene of Sinonovacula constricta by RACE technology. The results show that the full-length cDNA of S. constricta HSF1 gene was 2 026 bp; the open reading frame was 1 707 bp in length, encoding 568 amino acids; the 5' non-coding region was 196 bp in length; the 3' non-coding region was 123 bp in length. Amino acid sequence alignment and phylogenetic tree results show that HSF1 gene was the closest to the Crassostrea virginica, and its phylogenetic analysis was consistent with traditional morphological classification. The results of real-time PCR show that HSF1 gene was expressed in all tissues, and the relative expression of mantle membrane was the highest, followed by sputum, hepatopancreas and water tube, and the relative expressions in axillary and gonadal tissues were low.