Objective To explore the in vitro repair effect of collagen combined with ectoine on photo-induced skin damage. Methods A UVA-induced photo-damage model of ffbroblasts was established, including blank control group, negative control group, positive control group (quercetin) and sample group. The levels of Collagen Ⅰ and Collagen Ⅲ were detected by immunoffuorescence. A 3D epidermal skin model was constructed and induced by UVB, then randomly divided into blank control group, negative control group, positive control group (WY14643, dexamethasone) and sample group. Hematoxylin-Eosin (H&E) staining, immunoffuorescence and enzyme-linked immunosorbent assay (ELISA) were used to detect the number of sunburned cells, levels of inffammatory factors (IL-1α, TNF-α) and inffammatory mediator (PGE2). Results Compared with the blank control group, the levels of Collagen Ⅰ and Collagen Ⅲ in the negative control group were signiffcantly decreased (P<0.01). Compared with the negative control group, the levels of Collagen Ⅰ and Collagen Ⅲ in the positive control group and sample group were signiffcantly increased (P<0.01), with the increase rates reaching 92.50% and 100.00%, respectively. Compared with the blank control group, the number of sunburned cells and the levels of IL-1α, TNF-α and PGE2 in the negative control group were extremely signiffcantly increased (P<0.001). Compared with the negative control group, the number of sunburned cells in the positive control group was signiffcantly decreased (P<0.01), and the levels of IL-1α, TNF-α and PGE2 were extremely signiffcantly decreased (P<0.001). The number of sunburned cells and the levels of IL-1α, TNF-α and PGE2 in the sample group were extremely signiffcantly decreased (P<0.001), with the inhibition rates of 73.91% for sunburned cells, 69.29% for IL-1α, 55.36% for TNF-α and 52.80% for PGE2 in the sample group. Conclusion The combination of collagen and ectoine can effectively promote collagen synthesis, reduce the inffammatory response of photo-damage, and has a good repair effect on in vitro photo-damaged skin.