[Objectives]  To clone the Bradysia odoriphaga heat shock protein Hsp70 gene, analyze its gene sequence and mRNA expression profiles, and investigate its function in development and the thermal stress response. [Methods]  PCR primers were designed to amplify a full-length fragment of the Hsp70 gene based on the nucleotide sequence of B. odoriphaga obtained from transcriptome data. A real-time, fluorescence, quantitative detection system was established to detect Hsp70 expression in B. odoriphaga during exposure to high temperatures for different periods (30, 32, 34 and 36 ℃; 1, 2, 4, 6, 8, 10, 12 h) and after different recovery periods at 25 ℃ (1 h, 2 h). [Results]  The full-length B. odoriphaga Hsp70 gene was obtained and named BoHsp70 (GenBank accession number: MW250640). This gene contained a 1 971 bp open reading frame (ORF) and encoded 656 amino acids. Its amino acid sequence contains three Hsp70 family conserved sequences and a KDEL motif in the C-terminal region, indicating that Hsp70 is a member of the endoplasmic reticulum family of heat shock proteins. BLAST analysis of amino acid sequences indicates that BoHsp70 is very similar to the Hsp70 genes of Dipteran insects, and it clustered on the same branch as Dipteran Hsp70 genes on a phylogenetic tree. BoHsp70 was expressed in different developmental stages of B. odoriphaga. Expression was higher in male adults than in females and was significantly different in the heads of male and female adults. Exposure to a high temperature induced expression of BoHsp70 which peaked after 1-2 h. BoHsp70 expression decreased with the duration of exposure at 30, 32 and 34 ℃, but remained constant over time at 36 ℃. After heat shock treatment, BoHsp70 expression decreased with the duration of recovery time at 25 ℃. [Conclusion]  Collectively, these findings indicate that B. odoriphaga can regulate BoHsp70 expression in response to high temperature stress.