Objective:To investigate the protective effect and mechanism of Acronychia pedunculata water extracts on UV-induced light damage of human keratinocytes.Methods:The experiment was conducted from December 2018 to April 2020 in the Guangxi Medical University Laboratory of Genetics. The photoaged keratinocyte model was used, the cells were co-cultured with different concentrations of Acronychia pedunculata water extracts. The cell proliferation rate was detected by CCK-8 method. The levels of reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and total antioxidant capacity (T-AOC) of cells were detected by a test kit. The levels of IL-1β, IL-6 and tumor necrosis factor-alpha (TNF-α) were determined by ELISA.Results:The proliferation of HaCaT cells was promoted by 0.5 mg/L-2.0 mg/L of the extracts. Compared with control group, the proliferation rate of HaCaT cells in the experimental group was significantly increased ( P<0.05). Compared with control group, the contents of ROS was decreased ( F=214.67, P<0.05), MDA was decreased ( F=811.88, P<0.05), SOD was increased ( F=28.95, P<0.05), CAT was increased ( F=213.31, P<0.05), GPX was increased ( F=65.10, P<0.05), T-AOC was increased ( F=305.58, P<0.05), IL-1β was decreased ( F=15.46, P<0.05), IL-6 was decreased ( F=59.2, P<0.05), and TNF-α was decreased ( F=33.13, P<0.05). Conclusions:The extracts of 0.5-2.0 mg/L of Acronychia pedunculata have protective effects on the photoaging cell model, which may be related to the increase of SOD, CAT, GPX and other antioxidant enzymes and the level of T-AOC in photoaging HaCaT cells, and the decrease of ROS, MDA content and the expression of inflammatory cytokines.