Objective:To evaluate the safety and efficacy of 27G micro-incision vitrectomy surgery (MIVS) combined with intravitreal injection of ranibizumab (IVR) in the treatment of retinopathy of prematurity (ROP) with early intervention failure.Methods:Retrospective case series was performed. Fourteen eyes (11 infants) with ROP who underwent 27G MIVS combined with IVR were included from March 2016 to January 2018 in Shenzhen Eye Hospital. Among them, there were 5 males with 7 eyes, 6 females with 7 eyes. The average gestational age of the infants was 28.12±0.90 weeks; the average birth weight was 1 023.64±200.96 g. Before the early clinical intervention, 1 infant (2 eyes) had ROP in zone Ⅰ stage 3 with plus disease, 8 infants (10 eyes) had ROP in zone Ⅱ stage 3 with plus disease, and 2 infants had ROP in aggressive posterior ROP. Six eyes underwent laser photocoagulation, while 8 eyes received laser therapy combined with IVR. Six eyes of stage 4A ROP and 8 eyes in stage 4B. Retinal detachment was detected with a mean of 10.44±9.21 weeks. At the time of surgery, the average post-conceptional age was 48.02±8.09 weeks. All the affected eyes were treated with standard sclera with three incisions 27G MIVS. During the operation, only local vitrectomy was performed to release and clear fibroascular proliferation in the optic disc, anterior macular area and pericristal area. After surgery, 10 mg/ml of ranibizumab 0.03 ml was injected into the vitreous cavity. The average follow-up time was 23.36±8.34 months. The primary objectives were the condition of retinal reset, ROP progression control and complications.Results:All patients had uneventful surgeries with an average duration of 32.86±9.35 mins. Of the 14 eyes, 12 eyes (85.71%) were controlled, 8 eyes (57.14%) had a good rearrangement of macular structure, while 4 eyes with macular traction. Two eyes had ROP progression, recurrence of retinal detachment, posterior synechia. Complicated cataract was in 1 eye. Proliferative vitreoretinopathy and retinal detachment was in 1 eye after 7 months the operation.Conclusion:27G MIVS combined with IVR is a safe and effective treatment for ROP with early clinical intervention failure.