Abstract: A device for continuous seawater desalination of and a method thereof. A hydrophobic carbon nanotube composite membrane is made of a hydrophobic polymer and carbon-based materials, and the carbon-based materials are, such as, carbon nanotubes or graphene. The hydrophobic carbon nanotube composite membrane is perforated to obtain the hydrophobic carbon nanotube composite membrane having micrometer-nanometer multi-level pore structure using laser light. Further, a surface is coated with a photothermal-electrothermal responsive polymer to increase electric joule heat and photothermal effects to increase energy utilization efficiencies, and the hydrophobic carbon nanotube composite membrane having multi-level pore structure and electrothermal effects and photothermal effects is finally obtained.