A super-hydrophilic carbon nanotube composite film includes a carbon nanotube layer, a polydopamine layer and a silicon dioxide layer. The carbon nanotube layer includes a plurality of carbon nanotubes and defines two opposite surfaces. The polydopamine layer is on at least one surface of two opposite surfaces of the carbon nanotube layer, and the polydopamine layer includes a plurality of polydopamine nanoparticles. The silicon dioxide layer is on a surface of the polydopamine layer away from the carbon nanotube layer, and the silicon dioxide layer includes a plurality of amino-containing silica nanoparticles, and the plurality of amino-containing silica nanoparticles are grafted onto the surface of the polydopamine layer.