The WD40 protein, also known as the WD-repeat protein, contains 6-16 copies of the conserved domain, starting from Gly-His to tryptophan-aspartate (Trp-Asp, WD). The WD40 protein contains numerous members and composed a transcription factor (TF) family that plays important roles in plant responses to stress stimulus. Autophagy-related protein is a type of WD40 transcription factorTF involved in a variety of life activities such as plant growth, development, metabolism and response to adverse stimulus. However, the research on WD40 protein is dominated by herbaceous plants, and there are few studies on woody plants trees, especially the autophagy-related protein. Walnut is one of the major economic tree species that is composed of the multi-faceted poverty alleviation project in China. It plays an important role in promoting the regional economic development. However, in recent years, as the global environmental changes, environmental factors have seriously hampered the development of the walnut industry. Therefore, screening and characterization of walnut adversity response related genes and mechanisms will promote the selection and breeding of walnut resistant varieties, which may further improve the overall benefits of China's walnut industry. At present, there are few reports on the molecular mechanism of stress response in walnut planttree, therefore, exploring the stress response related genes and verifying the adaptive mechanism is urgently needed. In order to better explore the resistance mechanism of walnut tree and screen the genes related to stress resistance, in this study, an autophagy-related protein 18a (ATG18a) belong to WD40 TF was cloned from Juglans regia, which was named as JrATG18a. The basic biological function of JrATG18a was predicted by comparison the tissue expression profiles under abiotic stress-heat (45℃), cold (5℃), drought (20% PEG6000) and plant hormone treatments [2 mg/L salicylic acid (SA), 0.1 mmol/L ABA, 100 mg/L jasmonic acid (JA)] using the bioinformatics and gene expression techniques. The treatment time is 0, 3, 6 12, 24 h and the tissue includes leaf and root. The results showed that the open reading frame (ORF) of the JrATG18a gene was 1371 bp, the coding polypeptide contained 456 amino acids, the molecular weight was 50.746 KDa, and the theoretical isoelectric point was 5.97. JrATG18a shared close evolution with the ATG proteins from Fragaria vesca, Malus domestica, and Prunus persica. The three-dimensional structure of JrATG18a protein is presumed to be similar to that of strawberry FvvATG18a and apple MdATG18a, suggesting that JrATG18a may share similar functions with FvvATG18a and MdATG18a. A 2090 bp upstream promoter segment was isolated and predicted to contain abundant cis-elements, among which some are stress response related elements, such as heat shock element (HSE), low temperature response (LTR), SA and MeJA, implying the potential role of JrATG18a in walnut plant stress response and may involve in auxin signaling pathways. Then the expression profiles of JrATG18a under heat, cold, drought, SA, MeJA ABA and ABA JA treatments were analyzed by qRT-PCR. The results, and showed that JrATG18a gene could be induced by heat, cold, drought, SA, MeJA, ABA treatments with root and leaf tissue specificity. These results suggested that JrATG18a could response to stress and involve in walnut adaptation to adverse environment, JrATG18a is an effective candidate gene for walnut molecular breeding.