A facile one-step immersion co-precipitation method has been developed to fabricate an inorganic–organic composite membrane with three-dimensionally (3D) interpenetrating porous structures via incorporating ordered mesoporous silica (OMS) into polyvinylidene fluoride (PVDF). The composite membranes possess high surface area, excellent hydrophilicity and ultrahigh water fluxing capability (224.5 L m−2 h−1). It shows an excellent dynamic adsorption capacity (14.5 mg g−1) for methylene blue, which is ∼9.7 times higher than that of the pure PVDF membranes. Moreover, the composite membrane containing amino-functionalized OMS exhibits good adsorption capacity (1.5 mg g−1) for Cu(II) ions, thanks to the numerous amino groups in the mesopore walls. Importantly, the composite membranes can be easily regenerated, retaining their adsorption performance. Our findings open up the possibility for the mass fabrication of functional porous membranes for continuous and scalable water treatment.