Gamma-phase cesium lead tri-bromide perovskite nanocrystals (gamma-CsPbBr3 NCs) possess potentially photo-catalytic degradation ability and long-term stability. However, their serious aggregation issue decreases their active surface area, and the recombination of photo-generated hole-electron pairs weakens their photo-catalytic property. Furthermore, these NCs can be easily absorbed on the surface of dyes [e.g., methylene blue (MB)] or dissolved in the dye solution during the photo-catalytic degradation process, thus reducing the amount of gamma-CsPbBr3 NCs and their photo-catalytic degradation ability. Besides, the residual gamma-CsPbBr3 NCs in the photo-catalytic degradation products also present the toxicity issue (containing Pb) and are hazardous to the ecological environment and human health. In the present study, we fabricated gamma-CsPbBr3 NCs/polymethyl methacrylate electrospun nanofibrous membranes (gamma-CsPbBr3 NCs/PMMA ENMs) by using electrospinning technology to solve the above problems. It is found that the synthesized gamma-CsPbBr3 NCs/PMMA ENMs show a large surface area and the abundant functional groups on their surfaces, which are benefit for forming multiple kinds of chemical bonding effect between gamma-CsPbBr3 NCs and PMMA ENMs. In addition, gamma-CsPbBr3 NCs could disperse homogeneously in or on the surface of PMMA ENMs. These abundant chemical bonds and homogeneous distributions of gamma-CsPbBr3 NCs on the surface of PMMA ENMs can significantly decrease the recombination of photo-generated hole-electron pairs and toxicity issue of gamma-CsPbBr3 NCs during the photo-catalytic degradation process. Exhilaratingly, gamma-CsPbBr3 NCs/PMMA ENMs could maintain a superior photo-catalytic degradation ability toward various dyes and reveal a high photo-catalytic degradation efficiency of 99.18% in 60 min for MB. Published under license by AIP Publishing.