Abstract: Using COMSOL multiphysics software, a thermo-mechanical coupling model of the arc additive manufacturing arc on the deposited layer was established. The substrate and welding wire materials were selected as 304stainless steel, and the shielding gas was pure argon. The influence of the total height of the deposited layer on the surface heat flux density, pressure distribution, current density and electromagnetic force distribution of the deposited layer was studied.The results show that the peak heat flux increases with the increase of the layer height. Compared with that of the non-cladding layer, the peak heat flux density of the surface of the cladding layer at 20 mm layer height increases by 136%.The flow velocity at the edge of the deposited layer increases, resulting in a low pressure zone, and the minimum pressure decreases with the increase of the height. Since the conductivity of the deposited layer is higher than that of the ionized argon,the current preferentially passes through the deposited layer, and the current density on the top surface of the deposited layer increases significantly. The radial current in the deposited layer is smaller, and the electromagnetic force directed to the center is generated with the axial current under the self-induced magnetic field. And the heat flux density, pressure distribution,current and magnetic fields remain stable when the deposited layer height reaches 20 mm.