AIM:To compare the effectiveness and safety of intravitreal injection of conbercept(IVC)and intravitreal injection of ranibizumab(IVR)for type 1 retinopathy of prematurity(ROP).METHORDS: A retrospective case series observation was carried out. Clinical data of patients with type 1 ROP treated with IVC(46 cases, 91 eyes)or IVR(55 cases, 109 eyes)from August 2018 to January 2020 in Xijing Hospital were collected. Regression, progression, recurrence, retreatment of ROP, the proportion of adverse outcomes and ocular and systemic complications were all analyzed.RESULTS:All the 101 infants(200 eyes)with type 1 ROP treated with intravitreal injection of anti-vascular endothelial growth factor(VEGF)were enrolled, in which 20 eyes with aggressive posterior ROP(AP-ROP), 86 eyes with threshold ROP, and 94 eyes with type 1 pre-threshold ROP were included. There were no statistical differences in the basic conditions and the severity of ROP between the two groups before treatment(P>0.05). There was no difference in the primary cure rate between IVC and IVR groups(93.4% vs 87.2%, P>0.05). A total of 6 eyes(6.6%)developed ROP recurrence in the IVC group, in which 2 eyes received a second IVC, and 4 eyes were treated with laser photocoagulation(LP). In the IVR counterpart, 11 eyes(10.1%)developed ROP recurrence, among them 4 eyes underwent another IVR, and 11 eyes were treated with LP. The recurrence interval was 11.7±4.13wk and 9.82±4.02wk in the IVC and IVR groups. All these results of recurrence showed no significant statistical difference between these two groups(P>0.05). There was no progression of ROP appeared in IVC group. The progression of ROP developed in 3 eyes after initial ranibizumab injection, among them retinal fibrous proliferation and hemorrhage treated with LP in 2 eyes, and tractional retinal detachment treated with vitrectomy in 1 eye. No drug or injection related side effect was observed in infants of both groups. There were some adverse prognosis, such as temporal retinal folds, smaller angle between upper and lower temporal retinal vessel trunks caused by retinal vascular traction in 3 eyes in IVR group during the long-term follow up.CONCLUSION: Both IVC and IVR are effective and safety choices for the treatment of ROP. There was no significant difference between the first cure rate and the recurrence rate. Some of the most severe cases treated by IVR were at risk for progression or poor prognosis that need to be followed up for a long time.