Objective To explore the effect of ablative fractional carbon dioxide laser combined with medical sodium hyaluronate skin repair gel on skin elasticity in patients with postpartum striae gravidarum. Methods A total of 76 patients with postpartum striae gravidarum admitted to Donghai County Maternal and Child Health Hospital from October 2023 to October 2024 were selected as the research subjects. According to the random number table method, they were divided into the control group and the observation group, with 38 patients in each group. The control group was treated with ablative fractional carbon dioxide laser, and the observation group was treated with medical sodium hyaluronate skin repair gel on the basis of the control group. The skin elasticity, collagen ffber proportion, striae gravidarum regression rate and adverse reaction rate were compared between the two groups. Results The skin elasticity parameter of the observation group at 12 weeks after treatment was higher than that of the control group (P<0.05). The rate of collagen ffber proportion >50% in the observation group after treatment was higher than that in the control group (P<0.05). The striae gravidarum regression rate of the observation group was higher than that of the control group (P<0.05). The incidence of adverse reactions in the observation group was lower than that in the control group (P<0.05). Conclusion The application of ablative fractional carbon dioxide laser combined with medical sodium hyaluronate skin repair gel can promote the recovery of skin elasticity and collagen reconstruction in patients with postpartum striae gravidarum, effectively improve the regression effect of striae gravidarum, and has good overall safety.