Objective To explore the effect of CO2 fractional laser on the repair of hypertrophic scar after burn in mice and the mechanism of the TP53/MMP1 signaling axis. Methods A total of 36 C57BL/6 mice were used to establish the dorsal hypertrophicscar model after burn, followed by CO2 fractional laser intervention. Scar area changes were recorded by gross observation. HE staining was used to observe the morphological changes of scar tissue, and Masson's trichrome staining was used to assess the deposition and arrangement of collagen fiber. RT-qPCR and Western blot were used to detect the expression levels of Collagen Ⅰ, Collagen Ⅲ, α-SMA, TP53/p53, and MMP1 in scar tissue. Furthermore, shTP53 and shTP53+oeMMP1 intervention models were constructed by lentiviral transfection to observe the effects of TP53 knockdown and MMP1 overexpression on the reparative effect of fractional CO2 laser. Results Compared with the control group, the model group showed hyperplasia of cells and fibrous tissue, epidermal thickening, densely and disorderly arranged collagen fibers, and elevated mRNA and protein expression of Collagen Ⅰ, Collagen Ⅲ and α-SMA in scar tissues (P <0.05). Compared with the model group, the relative residual wound area decreased significantly on days 7 and 14 after CO2 fractional laser treatment (P <0.01), accompanied by thinned epidermis, reduced collagen deposition and more regularly arranged collagen fibers. The mRNA and protein expression of Collagen Ⅰ, Collagen Ⅲ and α-SMA were all decreased (P <0.05). The mRNA expression of TP53 in the model group was extremely significantly lower than that in the control group (P <0.0001), and the protein expression of p53 was significantly decreased (P <0.01). The mRNA expression of TP53 and protein expression of p53 were increased after fractional CO2 laser treatment (P <0.05). Under the background of fractional CO2 laser intervention, compared with the shNC group, the shTP53 group showed extremely significantly decreased TP53 mRNA expression (P <0.0001), decreased p53 protein expression (P <0.05), significantly decreased MMP1 mRNA expression (P <0.01), and decreased MMP1 protein expression (P <0.05). Meanwhile, the relative residual wound area in the shTP53 group was increased on days 7 and 14 (P <0.05); the mRNA and protein expression of Collagen Ⅲ were significantly increased (P <0.01), and the mRNA and protein expression of Collagen Ⅰ and α-SMA were increased (P <0.05). Compared with the shTP53 group, the oeMMP1 group presented extremely increased mRNA and protein expression of MMP1 (P <0.0001 and P <0.001, respectively), while there were no statistically significant differences in TP53 mRNA or p53 protein expression (P >0.05). The relative residual wound area was decreased on days 7 and 14 (P <0.05), and the tissue structure and collagen deposition were improved. Meanwhile, the mRNA expression of Collagen Ⅰ was significantly decreased (P <0.01), and the mRNA expression of Collagen Ⅲ, α-SMA as well as the protein expression of Collagen Ⅰ, Collagen Ⅲ and α-SMA were all decreased (P <0.05). Conclusion CO2 fractional laser can facilitate the repair of hypertrophic scar after burn in mice, improve scar tissue structure and reduce abnormal collagen deposition. Its mechanism may be related to the up-regulation of the TP53/MMP1 signaling axis and the promotion of extracellular matrix remodeling.