Abstract: 【Objective】Cloned the castor bZIP transcription factor gene RcbZIP44 and analyzed its expression characteristics to provide reference for exploring the biological functions of bZIP transcription factors in castor growth and development and under abiotic stress.【Method】The bZIP transcription factor gene family member RcbZIP44 from the castor variety Tongbi No. 5 was cloned，bioinformatics analysis on its sequence was performed，the tobacco transient expression system was used to conduct subcellular localization analysis on the RcbZIP44 protein. The expression pattern of RcbZIP44 gene in different tissues and under abiotic stress was detected by real-time fluorescence quantitative PCR.【Result】The cloned full-length cDNA of the RcbZIP44 gene was 612 bp，containing a 456 bp open reading frame（ORF），encoding 151 amino acid residues. There was no transmembrane region and signal peptide structure. It was an unstable hydrophilic protein with 21 potential phosphorylation sites. The secondary structure was mainly consisted of α-helix and was located in the nucleus. The promoter region of the RcbZIP44 gene contained hormone response elements（ABRE，GARE-motif， TATC-box，TGACG-motif），stress response elements（LTR，ARE，MRE），etc. It was speculated that the RcbZIP44 gene played an important role in abiotic stress. The relative expression level of RcbZIP44 gene in stems was the highest，significantly higher than that in roots，cotyledons and true leaves（P<0.05），indicating that it had obvious tissue expression specificity. Under abscisic acid（ABA），salt，drought and low-temperature stresses，RcbZIP44 gene showed different expression patterns in leaves and roots. RcbZIP44 gene was sensitive to low-temperature stress，and the relative expression level was the highest when treated for 6 h. RcbZIP44 gene showed an expression pattern of increasing first and then decreasing under ABA and drought stress，and the relative expression level was the highest when treated for 12 h. In salt stress，the expression of the RcbZIP44 gene was relatively stable.【Conclusion】The protein encoded by RcbZIP44 gene contains bZIP-plant-GBF1 domain which is unique in bZIP family. It mainly plays a regulatory role in stems. RcbZIP44 gene is induced by abiotic stresses such as ABA，salt，drought and low temperature. It is speculated that RcbZIP44 gene plays an important regulation role in castor growth and development and in response to abiotic stress.