The invention provides a carbon nano material /
metal nano material composite nano ink which comprises
solvent, an additive, a carbon nano material and a
metal nano material. The carbon nano material /
metal nano material composite nano ink is characterized in that the
solvent can comprise water,
alcohol organic solvent (
ethanol(
alcohol), isopropanol, n-
butanol and the like), ester
organic solvent (
ethyl acetate,
butyl acetate,
ethylene-propylene acetate and the like),
benzene organic solvent (methylbenzene, dimethylbenzene and the like) and
ketone organic
solvent (
cyclohexanone,
acetone, methylethylketone,
butanone and the like); the additive comprises surfactant, pH value stabilizer, defoaming agent, diluter, reinforcer and the like; the carbon nano material comprises a single-layer
carbon nanotube, a double-layer
carbon nanotube, a multi-layer
carbon nanotube and
graphene; the metal (
copper, silver, gold,
platinum,
nickel and the like, also including an
alloy nano material, an ITO metal composite nano material and the like) nano material further comprises a metal
nanoparticle, a
metal nanowire or a metal
nanotube; the components of the nano ink must include one carbon nano component and one metal nano component, such as a single-layer carbon
nanotube and
copper nanowire composite ink, a double-layer carbon
nanotube and silver
nanowire composite ink, a single-layer carbon nanotube and
silver nanoparticle composite ink or any other possible combination; the components can be regulated according to specific applications; and a composite nano conductive film can be formed on different bases through different electronic printing processes. The ink can be used in the printing of a flexible base material and can be conveniently prepared into a flexible conductive film.