AIM: To evaluate efficacy of intravitreal ranibizumab (IVR) therapy for aggressive posterior retinopathy of prematurity (ROP), threshold ROP disease and type 1 pre-threshold ROP. METHODS: A retrospective analysis was performed on 40 patients (76 eyes) who had IVR as the primary treatment for ROP from April 2017 to January 2018. According to disease pathogenic features, the 76 eyes were divided into three groups: aggressive posterior ROP (AP-ROP) group (16 eyes), threshold ROP group (28 eyes) and type 1 pre-threshold ROP group (32 eyes). The characteristics of patients and lesions situation before the first intravitreal injection, and posttreatment fundus outcomes determined by wide-angle RetCam fundus imaging were recorded. RESULTS: The birth weight and postmenstrual age of first IVR treatment in AP-ROP, threshold ROP, and type 1 pre-threshold ROP groups were significant difference (1087.50±246.78, 1103.75±168.30, 1257.03±210.82 g, P=0.005; 34.50±1.46, 36.89±2.97, 36.50±2.36wk, P=0.008), while the gestational age was not difference (28.00±2.00, 28.54±1.90, 28.59±1.43wk, P=0.510). The retina hemorrhage ratio (with/without: 14/2, 8/20, 5/27), iris neovascularization or vascular engorgement ratio (with/without: 12/4, 11/17, 6/26), and the zone I (inside/outside: 16/0, 2/26, 5/27) in AP-ROP, threshold ROP, and type 1 pre-threshold ROP group were difference significantly (all P<0.05). The regression rates were 37.5%, 92.86%, and 100%, and the recurrence rates were 62.5%, 7.14%, and 0 in AP-ROP, threshold ROP, and type 1 pre-threshold ROP group, respectively (both P<0.05). The recurrence eyes were cured by secondary IVR or retinal laser photocoagulation. CONCLUSION: IVR is an effective treatment for all types of ROP. The regression of AP-ROP is significantly lower than type 1 pre-threshold and threshold disease. Birth weight, retinal hemorrhage, iris neovascularization or vascular engorgement and lesions located in zone I may be associated with AP-ROP recurrence and retreatment, which should be noted in follow-up.