The invention discloses a multi-
physics field-assisted 
electric resistance welding method for 
dissimilar metal material. The multi-
physics field-assisted 
electric resistance welding method for the 
dissimilar metal material includes steps that exerting a magnetic-sound 
composite field to a piece to be welded after performing oil removing and acid 
pickling so as to activate the surface of the piece to be welded, carrying out 
electric resistance welding on the 
dissimilar metal under the magnetic-sound 
composite field environment till solidifying the 
metal at the weld joint, cooling to a 
room temperature, and stopping exerting the 
composite field to finish 
welding the dissimilar 
metal. The multi-
physics field-assisted electric resistance 
welding method for the dissimilar 
metal material has advantages that by means of the stirring and shock excitation effects of the magnetic-sound composite field for the melt metal at the weld joint in the 
welding process, the primary 
crystal size is effectively reduced, the 
dislocation density in the 
crystal is increased, the size of the 
crystal grain tissue at the weld joint is refined, and the mechanical performance of the weld joint is improved; by means of the 
magnetic field and high-frequency vibration, the energy generated by 
elastic vibration is converted into the plastic flow energy of the metal material, the friction power of the welding interface and 
heat energy, the energy needed for melting 
base metal for the electric resistance welding can be lowered, and the energy is saved.