The invention discloses a preparation method of an ethylene propylene diene monomer/polyaniline/high density polyethylene composite conducting material. The preparation method comprises the following steps: (1) adding an aniline monomer to ethylene propylene diene monomer powder, and stirring evenly to obtain the swelled ethylene propylene diene monomer; (2) obtaining ethylene propylene diene monomer/polyaniline composite conducting powder; (3) obtaining ethylene propylene diene monomer/polyaniline/high density polyethylene composite particles; (4) obtaining the ethylene propylene diene monomer/polyaniline/high density polyethylene composite conducting material. The method is capable of obtaining the high-electrical conductivity composite material in case of relatively low polyaniline content; meanwhile, the method provides good processability, and is capable of effectively weakening the influence of the degradation of other properties of the composite material due to the increase of the polyaniline content.