A method for making a carbon nanotube-metal particle composite is provided. Carbon nanotubes, polymer monomers, a first solution containing metal ions, and a second solution containing carboxylic acid radical ions are provided. The carbon nanotubes and the polymer monomers are mixed in a solvent to form a first mixture. The polymer monomers are adsorbed on the carbon nanotubes. A second mixture is formed by mixing the first mixture, the first solution, and the second solution. The polymer monomers, the first solution, and the second solution react with each other to form a coordination complex mixture containing the metal ions. The coordination complex mixture is adsorbed on the surface of the carbon nanotubes. A reducing agent is added into the second mixture to reduce the metal ions of the coordination complex mixture to metal particles, simultaneously, the polymer monomers are polymerize to in situ form the carbon nanotube-metal particle composite.