The effects of walnut oil on wound healing and skin injury repair was observed in Sprague-Dawley (SD) rats, and mechanism of action was investigated. Normal SD rats were divided into an experimental group and a control group. Each group was observed at4 time points (day [D]3, D7, D14, and D21). In both groups, a skin wound was created on the back of the rats, with the spine as the central axis. In the experimental group, the wound was covered with walnut oil, and then bandaged and fixed with sterile gauze. In the control group, the wound was bandaged with vaseline gauze. At each corresponding time point, the wound area and wound healing time of each rat were examined. Epithelial cells of the wound tissues were observed using haematoxylin and eosin staining and immunohistochemical analysis,and the numbers of inflammatory cells and capillaries were counted. A western blot method was used to detect the expression of nuclear factor (NF)-κB and epidermal growth factor (EGF) in the wound tissues of both groups. Meanwhile, enzyme-linked immunosorbent analysis (ELISA) was used to detect the expression of transforming growth factor (TGF)-β1 and matrix metalloproteinase (MMP)-1 in rat sera. A total of 48 SD rats completed the experiment. Healing time of residual wounds in the experimental group was 10.0±3.5 days, which was significantly shorter than that in the control group (18.0±6.0 days) (p<0.05). The wound healing rates in the experimental group were 54.14 % (D3) and 91.2 3% (D7), whereas those in the control group were 22.12% (D3) and 54.84% (D7 (p<0.05).Histological examinations revealed no epithelial cells on D3, D7, D14, and D21 in both the experimental and control groups. However, the number of inflammatory cells decreased significantly and the number of capillaries increased significantly in the experimental group compared to control (p<0.05). NF-κB expression was significantly lower, EGF expression significantly higher in the in the experimental group. Conversely, ELISA showed a significant increase in the expression of TGF-β1 and MMP-1 in rat sera in the experimental group. So we conclude that walnut oil has significant effects in promoting the healing of skin defect wounds in SD rats.