Diabetic retinopathy(DR)is one of the main blinding eye diseases for people over the age of 50, and diabetic macular edema(DME)is the leading cause of vision loss is DR patients. The early diagnosis and early treatment is important. As OCT and FFA, mfERG, especially the retinal thickness, volume, retinal edema index quantitative indicators such as objective evaluation of macular edema, embodies the new progress of retinal imaging technology in recent years. OCT is a non-contact clinical application in recent years, noninvasive, high resolution of ophthalmic imaging examination, can do it on retinal ultrastructure observation and quantitative analysis, and the technology is relatively mature, become a routine inspection diagnosis of macular edema. Laser photocoagulation,intravitreous injection with Ranibizumab and vitrectomy is nowadays the important means for the treatment of intractable macular edema.