A stable 12-phase AC arc was generated by transformers at a commercial electric power system, and the arc behavior was characterized by image analysis. For the unique advantages, the multiphase AC arc was developed to apply to in-flight glass melting for the purpose of energy-saving and emission reduction. The effects of electrode configuration and sheath gas flow rate on the arc and melting behavior of granulated glass raw material were investigated. Results show that the discharge behavior and the high-temperature region can be controlled by the electrode configuration. The luminance area of the high-temperature region and its fluctuation reflect the discharge behavior. The vitrification degree of glass raw material is mostly dependent on the center temperature of arc. As sheath gas flow rate increases, the ratio of luminance area decreases and the center temperature of arc increases.