Abstract: Objective: To investigate the protective effect of Scutellaria baicalensis extract on ultraviolet (UVA)-induced photoaging in a fibroblast cell line (NIH3T3). Methods: The cellular photoaging model was established by UVA irradiation, and the protective effects of Scutellaria baicalensis extract on photoaging fibroblasts were investigated using CCK-8 assay, β-galactosidase staining, DAPI staining, and immunofluorescence staining. Results: Scutellaria baicalensis extract significantly promoted cell proliferation and migration of NIH3T3 cells(P<0.05), increased the cell viability of NIH3T3 cells after UVA irradiation, reduced UVA-induced cell apoptosis, and the expression of senescence-associated marker β-galactosidase (SA-β-gal). It also promoted the regeneration of endogenous type I and type IV collagen, reversing collagen loss induced by UVA irradiation, collectively contributing to the defense against cellular photoaging. Conclusion: Scutellaria baicalensis extract effectively inhibits the photoaging of NIH3T3 cells induced by UVA irradiation.