Abstract: Cataract surgery can increase the risk of diabetic macular edema (DME) and Irvine-Gass syndrome postoperatively in nonproliferative diabetic retinopathy (NPDR) patients. An accurate distinction between DME and Irvine-Gass syndrome in NPDR patients after cataract surgery is significantly important for the selection of subsequent treatment plans and guarantee of long-term vision quality. This article elaborates the differential diagnosis and prevention of DME, in order to provide a theoretical basis for the timely prevention, accurate diagnosis and standardized treatment of DME in NPDR patients after cataract surgery. (Chin J Ophthalmol, 2021, 57: 546-551)