〔Abstract〕 Objective To observe the preventive effect of red light irradiation on the prevention of postpartum infection with eutocia gestational diabetes mellitus (GDM). Methods The data of GDM women who delivered in Zhengzhou Second People's Hospital from March 2021 to February 2022 by vaginal delivery were retrospectively selected.A total of 49 puerpera who received conventional postpartum anti-infection intervention were selected as the control group, and 49 puerpera who received red light irradiation intervention on the basis of conventional anti-infection intervention were selected as the observation group. The postpartum clinical data, serum inflammatory factors and cervical microcirculation indexes were compared between the two groups. Results The postpartum fever rate and infection rate of the observation group were lower than those of the control group, and the differences were statistically significant (P < 0.05). The visual analogue scale (VAS) score and incision recovery time of the observation group were less than those of the control group 3 days after delivery, and the differences were statistically significant (P < 0.05). The levels of C-reactive protein (CRP), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the observation group were lower than those in the control group 3 days after delivery, and the differences were statistically significant (P < 0.05). The inner diameter of capillary, blood perfusion and microvascular diameter in the observation group were higher than those in the control group, and the differences were statistically significant (P < 0.05). Conclusion Red light irradiation can improve the cervical microcirculation of GDM women, help reduce postpartum inflammatory response, so as to effectively improve the prevention effect of postpartum infection.