In recent years, as the prevalence of diabetes has increased, the prevalence of proliferative diabetic retinopathy has also increased significantly. In our study, we found that proliferative diabetic retinopathy is often combined with retinal vein embolism, especially in some cases in the early stages, and advanced diabetic retinopathy leads to severe vision loss in patients due to fibrovascular proliferation, vitreous hemorrhage, retinal detachment, and severe macular edema. Despite total retinal photocoagulation, proliferative lesions continue to worsen in 20% of patients [4]. Vitrectomy can effectively remove blood from the vitreous, relieve retinal traction, reduce the appearance of retinal detachment, reduce macular edema, and create conditions for early total retinal photocoagulation, making it an effective method for treating proliferative diabetic retinopathy and improving visual function [5,6]. In the past, the indications for surgery in diabetic retinopathy were mostly selected in stage V and VI and after the patient had poor visual acuity and repeated vitreous hemorrhages, but at this time, most of the patients had severe proliferation of neovascular membrane, vitreous, macular edema and even retinal detachment, and their visual function had been severely impaired, which also increased the difficulty of surgery, poor recovery of postoperative visual function and many surgical complications. For this reason, we retrospectively analyzed diabetic retinopathy cases that were seen in our hospital and treated with combined vitrectomy surgery from August 2002 to January 2009, to investigate the impact of receiving surgery at certain visual acuity at different times on the prognosis of patients. Earlier studies on the treatment of proliferative diabetic retinopathy were conducted abroad. The Vitrectomy in Diabetic Retinopathy Study Group found that early surgical treatment maintained or improved the useful visual acuity of patients and reduced postoperative complications, which is consistent with our findings [7]. And recent studies have also shown that vitreous surgery can significantly improve patients’ vision-related quality of life [8]. In our study, 85.34% of those who maintained or improved their vision after combined vitrectomy and 31.90% of patients had two or more lines of visual acuity improvement, showing that combined vitrectomy for proliferative diabetic retinopathy is highly effective. There is a significant difference in the recovery of postoperative visual acuity when vitreous surgery is performed early in proliferative diabetic retinopathy compared with more advanced surgery, and early surgical treatment can significantly reduce the occurrence of complications. Because of early surgery, membrane separation is easier, complications are less frequent, and the entire laser treatment of the affected eye can be completed earlier, thus terminating the process of PDR and reducing macular edema. In all patients with diabetic retinopathy who underwent surgery, the percentage of intraoperative retinal fissures, intraoperative hemorrhage, and postoperative retinal detachment with vitreous hemorrhage increased significantly as the disease worsened. In our study, the proportion of patients with diabetic retinopathy, stage V and VI who developed complicating cataracts after surgery were 9.3%, 15.91% and 14.28%, respectively, and the difference in the proportion of complicating cataracts after surgery for diabetic retinopathy in different periods was not significant, probably because the occurrence of complicating cataracts was mainly related to surgical stimulation and postoperative intraocular environmental This may be due to the fact that the development of concurrent cataract is mainly related to the surgical stimulation and the postoperative intraocular environment, while the course of the disease has relatively little effect on the development of concurrent cataract. Our study suggests that vitrectomy is an effective method to treat proliferative diabetic retinopathy and improve visual acuity. Early surgery is performed to avoid complications such as difficult regression of macular lesions and difficult repositioning of retinal detachment, and to create conditions for performing late total retinal photocoagulation. Although some patients have vitreous hemorrhage, the stage level of diabetic retinopathy is not high, but due to venous embolism, still need early surgery, although some patients are in stage IV diabetic retinopathy, but their vision is already very poor and cannot be controlled by laser, they should be operated in time, therefore we think that although all vitreous hemorrhage in stage IV diabetic retinopathy is being operated. Through our study, we found that there are limitations in choosing the timing of surgery based on the existing stages of diabetic retinopathy, and that the patient’s visual acuity and previous treatment, as well as the patient’s glycemic control and blood pressure, should be combined to flexibly choose the timing of surgery. The surgeon should choose the indication and timing of surgery according to his or her technical ability and the patient’s visual acuity and intraocular vitreoretinal appreciation. In order to avoid missing the best treatment time.