The instability of graphene oxide (GO) membranes in aqueous solutions restricts their application in wastewater treatment through the membrane separation technology. In this work, a nanocomposite membrane (Sm-MOF/GO) composed of samarium metal–organic frameworks (Sm-MOFs) and GO nanosheets was successfully fabricated via the filtration of the corresponding Sm-MOF/GO dispersions. The in situ growth of Sm-MOF with aqueous stability on the GO sheets prevented the adjacent GO layers from expanding in aqueous solutions, thus endowing the prepared Sm-MOF/GO membrane with a stable membrane skeleton structure. Besides, the successful loading of Sm-MOF enlarged the layer space of the composite membrane, which was beneficial for higher permeance. The optimization of the Sm-MOF loading contents was also investigated to prepare M-X (where X represents the mass ratio of the MOF raw material to the total mass of the reactants). Subsequently, the fabricated M-0.31 possessed a high permeance of 26 L m⁻² h⁻¹ bar⁻¹, which was 3 times higher than that of a pure GO membrane; moreover, high rejections (>91%) to rhodamine B and methylene blue were obtained. After continuous 5.5 h filtration, the excellent rejection was still maintained as expected, indicating the long-term stability of M-0.31.