【Objective】The bHLH transcription factor family is an important family of transcription factors in eukaryotes, which plays an important role in plant growth and development, secondary metabolism and stress response. Analysis of the response pattern of bHLH transcription factor gene OsbHLH109 (LOC_Os01g67480) to stress and hormones in rice (Oryza sativa L.) could provide a theoretical basis for further researches on the functions of OsbHLH109 in stress and hormone responses.【Method】The bioinformatics of OsbHLH109 was analyzed, and the expression patterns of OsbHLH109 in different tissues of Rice Zhonghua 11 under different hormone and abiotic stresses were analyzed by quantitative PCR (qRT-PCR).【Result】The encoding region of OsbHLH109 was 1 164 bp in length, containing 6 exons and encoding 388 amino acids, which was a bHLH transcription factor containing a conserved domain of HLH. Phylogenetic analysis showed that OsbHLH109 was closely related to the homologous proteins in monocots and Dicotyledones. The analysis of cisacting elements showed that the promoter region of OsbHLH109 contained 24 plant hormone response cis-elements and 25 environmental stress response cis-elements. The qRT-PCR analysis showed that OsbHLH109 was expressed in roots, stems, leaves and young panicles of rice, but the expression level was the highest in leaves. The results of hormone treatment response expression profile analysis showed that the response expression differences of OsbHLH109 in leaves to 6-Benzylaminopurine (6-BA), indole acetic acid (IAA), gibberellic acid (GA3) and abscisic acid (ABA) treatments all reached significant levels. The results of stress treatment response expression profile analysis showed that the response of OsbHLH109 to low temperature stress, drought stress, high temperature stress and salt stress were significantly different in leaves, indicating that the expression of OsbHLH109 was induced by 6-BA, GA3, IAA, ABA, high temperature, low temperature, PEG6000 and NaCl, which suggested that OsbHLH109 was essential for the abiotic stress responses in rice.【Conclusion】Rice OsbHLH109 is a member of the bHLH transcription factor family and is highly expressed in leaves. The expression of OsbHLH109 gene is regulated by high temperature, low temperature and salt stress, and responds to hormone signals such as 6-BA, IAA, GA3 and ABA. It is predicted that it may be involved in abiotic stress response of rice through ABA and other hormone signal transduction pathways. [ABSTRACT FROM AUTHOR]