Müller cells are the most important glial cells in the vertebrate retina. They extend from the inner limiting membrane to the outer membrane through the entire retina, participate in the blood-retinal barrier, and actively participate in retinal development and promote the maintenance of retinal homeostasis through many intracellular mechanisms. Müller cells play an important role in the development of diabetic retinopathy. The pathophysiological changes in diabetic retinopathy remain to be further studied. This article reviews the pathophysiological changes of Müller cells in diabetic retinopathy and the recent research progress.