The invention discloses a water-proof and dehumidifying modified antirust agent for ships. The water-proof and dehumidifying modified antirust agent for the ships comprises the following raw materials: calcium sulfonate, ammoniacal copper quaternary, sodium hexametaphosphate, glutaraldehyde, carbon nanotubes, sodium borohydride, polyvinyl alcohol, sodium sulfonate, zinc phosphate, zinc powder, zinc stearate, magnesium stearate, a silane coupling agent KH-570, aqueous polyurethane, azobisisobutyronitrile, benzotriazole, diammonium hydrogen phosphate, triethanolamine, fatty acid, trimethylolpropane, sodium dialkyl dithiocarbamate, polyisobutylene succinimide, methyl benzoate, polytetrafluoroethylene, octadecyl trimethylammonium chloride, nonylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, dodecylbenzenesulfonic acid, 1,2-benzisothiazolin-3-one,3-iodo-2-propynylbutyl carbamate, a modifying waterproof agent, a modifying hydrophobic agent and a modifying auxiliary agent. The water-proof and dehumidifying modified antirust agent for the ships is applied to instrument prevention of instruments on the ships, and has excellent water-proof and dehumidifying performance and antirust performance.