Müller cells(MCs)are the most common glial cells in the human retina. They provide homeostatic, metabolic, and functional support to neurons. MCs play a critical role in regulating extracellular space volume, ion and water homeostasis, and maintaining the blood-retinal barrier. They release gliotransmitters and other neuroactive molecules, influencing synaptic activity through neurotransmitter recycling. All these functions directly or indirectly alter neuronal activity. MCs support the survival of photoreceptors and neurons, are responsible for the structural stability of the retina, and act as regulators of immune and inflammatory responses. They are activated in response to almost all pathogenic stimuli. Reactive MCs have neuroprotective effects, but excessive activation of MCs under pathological conditions can withdraw neuronal protection and lead to neuronal degeneration. Thus, MCs may play a double-edged sword role in the pathogenesis of macular edema due to retinal vein occlusion(RVO-ME). Understanding the response of MCs to pathological stimuli and their protective and damaging effects on the retina and macula is crucial for studying the pathogenesis and guiding the treatment of RVO-ME. This article reviews the role of MCs in RVO-ME, aiming to provide new strategies for the treatment of RVO-ME.