【Objective】 Grapes are typical accumulators of tartaric acid, which not only affects the taste of grape berries but also determines the color, texture, microbial stability, and aging potential of wine. 【Methods】 The bHLH transcription factors are involved in the regulation of various biological processes in plants, including growth and development, secondary metabolism, and stress responses. Our research group has previously screened a bHLH transcription factor related to tartric acid biosynthesis. In this study, using ‘Traminer’, ‘Marselan’ wine grape as experimental material, we cloned the tartaric acid content related transcription factor VvbHLH79 by PCR. We performed bioinformatic and subcellular localization analyses of VvbHLH79. Furthermore, we measured the tartaric acid content and VvbHLH79 expression levels in grape berries at different developmental stages using HPLC and qRT-PCR techniques. We also constructed a plant expression vector and the expression and tartaric acid content of VvbHLH79 were detected after transient transformation of young grape berries using Agrobacterium-mediated fruiting pedicle infection, in order to clarify the role of the VvbHLH79 gene on the content of tartaric acid in grape berries.These results provide a foundation for further exploration of the molecular mechanisms underlying the regulation of tartaric acid biosynthesis by VvbHLH79. 【Results】 The results showed: (1) A grapevine VvbHLH79 gene was obtained by RNA-seq sequencing, with a full-length CDS sequence of 831 bp, encoding 277 amino acids, a relative molecular weight of 66.22 kD, and a theoretical isoelectric point of 5.15. It belongs to the class of unstable hydrophilic proteins without signal peptides and transmembrane structures. Amino acid residues 147-232 contain the bHLH-SF conserved domain, classifying it within the bHLH transcription factor family. The protein is localized in the cell nucleus. (2) Homologous sequence alignment and phylogenetic tree results showed that the grapevine VvbHLH79-encoded protein had the highest sequence similarity with the bHLH89-encoded protein in riverbank grape (Accession number: XP_034699340.1), with a sequence identity of 99.64%. (3) qRT-PCR analysis revealed a gradual decrease in VvbHLH79 relative expression levels during the development of ‘Traminer’ grapes fruits, decreasing by approximately 67.25% from veraison to harvest. HPLC results indicated that the accumulation of tartaric acid occurred mainly before the color change of the grapes, with a rapid decrease in tartaric acid content after the color change. (4) Transient overexpression of VvbHLH79 in low tartaric acid grape berries resulted in a significant increase in tartaric acid content, whereas silencing of VvbHLH79 in high tartaric acid grape berries resulted in a significant decrease in tartaric acid content, confirming that the VvbHLH79 gene positively regulates tartaric acid content. 【Conclusion】 This study suggests that the VvbHLH79 transcription factor may play a role in the tartaric acid biosynthesis pathway in grape berries.