Abstract: Alternating current and hot wire GMAW process is a kind of efficient welding process, the main arc of which is the traditional GMAW arc. Under the action of AC pulse preheating current, the filler wire can flow form a closed loop with the welding pool structure in the base metal. The current flows through the loop to generate resistance heat to preheat the filler wire. The filled wire preheated to high temperature will melt rapidly under the thermal influence of the liquid metal after entering the molten pool. In this experiment, the high efficiency hot wire GMAW process was studied. The study found the matching rules among the parameters such as the preheating current of the filler wire, the extension length of the filler wire, the distance between the filler wire, the main arc welding specification, etc. Finally, it was realized the deposition rate above 20 kg/h. Through the analysis of the influence rules of the above factors on the deposition efficiency, the results show that: compared with the traditional welding process, hot wire GMAW has obvious advantages in improving the deposition rate and deposition coefficient. This process has a broad application prospect in the field of high strength steel thick plate welding.