AIM:To seek the reasons and effective methods to treat the intractable high intraocular pressure (IOP) after vitrectomy of proliferative diabetic retinopathy (PDR).METHODS:Postoperative IOP of eyes with PDR after vitrectomy were retrospectively analyzed within 2 years in our hospital.RESULTS:Twenty-five eyes (21.0%) occurred intractable high IOP in 119 eyes.IOP in 18 (72.0%) of 25 eyes could be controlled by using medical treatment,while 7 eyes required surgery.19 (76.0%) of 25 eyes had high IOP within one week after surgery,the other 6 eyes had high IOP at 2 to 18 months after surgery.The reasons of postoperative high IOP happened in 3 months after surgery included pupil atresia in one eye and neovascular glaucoma in 4 eyes.These 4 eyes with neovascular glaucoma had received phacoemulsification cataract surgery.In 119 eyes,silicone oil injection was in 42 eyes (35.3%),C3F8 injection in 12 eyes (10.1%).In 25 eyes with postoperative high IOP,11 eyes had received vitrectomy combined with silicone oil injection (44%,P= 0.41).IOP had no statistically significant difference between the eyes with and without silicone oil.2 eyes were injected C3F8 (7.7%,P=0.83),IOP had no statistically significant difference between the eyes with and without C3F8.CONCLUSION:The intractable high IOP after vitrectomy treating PDR usually can be controlled by medication.Silicone oil as intraocular tamponade is not the primary factor for postoperative high IOP.As long-dated high IOP may be associated with neovascular glaucoma.Intraoperative or postoperative cataract extraction requires carefully consideration.