Abstract: The effect of applied magnetic field on metal transfer of twin-wire indirect gas shielded arc welding was studied in this paper.Both transverse and longitudinal magnetic fields were applied by excitation coil.The variation of magnetic induction intensity was measured by Tesla meter,and the metal drop lets transfer was captured by high-speed camera system.The variation of arc voltage and welding current were recorded by oscilloscope synchronously.Results showed that droplets diameter decreased and transition frequency increased with increasing of positive transverse magnetic intensity,while droplets diameter increased and transition frequency decreased with increasing of negative transverse magnetic intensity.The droplets would deflect after falling from wires and the deflection degree increased with increasing longitudinal magnetic intensity.The droplets deflected to cathode when positive longitudinal magnetic field was applied while deflecting to anode when negative longitudinal magnetic field was applied.