Abstract: Objective To investigate the efficacy and safety of 25-gauge plus(25G+) minimally invasive vitrectomy (PPV) combined with preoperative intravitreal injection of ranibizumab (IVR) at different intervals in the treatment of proliferative diabetic retinopathy (PDR). Methods A retrospective study was performed using data from 54 patients (65 eyes) who underwent the combination therapy of 25G+ PPV and preoperative IVR. According to the intervals between IVR and PPV, 65 eyes were divided into 2 groups: 21 eyes of 19 patients in Group A received IVR 3 d before PPV, and 44 eyes of 35 patients in Group B received IVR 7 d before PPV. After 10-36 months follow-up after operation, the differences of best corrected visual acuity (BCVA), intraocular pressure, intraoperative condition and postoperative complications between the two groups were analyzed. Results The BCVA of the two groups at 1, 3, 6 months and the last follow-up was better than that before treatment (P<0.05). The incidence of early postoperative vitreous hemorrhage in group B was significantly higher than that in group A (P<0.05). There was no significant difference in BCVA and intraocular pressure between the two groups (P>0.05). There was no significant difference in operation time, intraoperative hemorrhage, iatrogenic retinal tear, recurrent retinal detachment, neovascular glaucoma and late-stage postoperative vitreous hemorrhage between the two groups (P>0.05). Conclusions 25G+ PPV combined with both 3 d and 7 d preoperative IVR are effective strategies for the treatment of PDR, but PPV combined with 3 d preoperative IVR can effectively reduce the incidence of early postoperative vitreous hemorrhage.