In the current study, novel environmentally friendly and interfacially active carbon nanotubes/SiO2 nanomaterials (CNTs/SiO2) for emulsified crude oil separation were prepared via grafting nano-SiO2 on the surface of oxidized carbon nanotubes (Ox-CNTs). The structure of the as-prepared CNTs/SiO, was characterized by Fourier transform infrared spectroscopy, UV-visible absorption spectra, Raman spectra, X-ray diffraction spectra, thermogravimetric analysis, field-emission scanning electron microscope, and energy-dispersive X-ray spectroscopy. Besides, three-phase contact angles (theta) were employed to evaluate the wettability of CNTs/SiO2. Also, it was found that the theta value of CNTs/SiO2 was about 90 degrees. The nanomaterials with interfacial activity can spontaneously assemble at the oil-water interface, thus improving the droplet coalescence in the emulsion. Afterward, the demulsification performance was evaluated in crude-oil emulsions using the bottle test, which demonstrated that the demulsification efficiency demulsification efficiency could reach 87.40%. Also, the water phase was clear, while the optimum concentration and sedimentation time were 500 ppm and 30 min, respectively. Furthermore, the possible demulsification mechanism was evaluated by an optical microscope. The findings in this work might provide a novel environmentally friendly and interfacially active nanomaterial as a crude oil demulsifier.