<p>A three-dimensional transient model of the TIG (Tungsten Inert Gas)-MIG (Metal Inert Gas) hybrid arc and droplet was established. By adopting a unified set of “electrical-magnetic-thermal-force” control equations, it quantitatively analyzed the characteristics of current density, electromagnetic force, temperature, arc pressure, as well as their effects on droplet behavior. The results showed that the model exhibited a consistent trend between simulation and experiment within the welding current range of 180–280 A. Three current paths existed in the hybrid arc, namely wire-workpiece, workpiece-tungsten electrode, and wire-tungsten electrode. Among these, the wire-tungsten electrode path was unique to the hybrid arc, with its current proportion reaching as high as 63%–69%. With the increase in welding current, the droplet volume decreased while the transfer frequency increased. The arc temperature field became more stable, and the electromagnetic force increased significantly. Moreover, under high current conditions (&gt; 240 A), the hybrid arc pressure was more dispersed spatially, and droplet transfer became more stable, which was conducive to suppressing weld defects. This study realized the quantitative analysis of the coupling mechanisms between the two arcs and between the arc and droplet, providing theoretical support for the optimization of TIG-MIG hybrid welding process parameters. It is of great significance for improving weld quality and promoting the industrial application of TIG-MIG hybrid welding technology.</p>