Abstract: With the help of high-speed camera, the image signals of arc in the ignition discharge process and arc stable combustion process were observed, and the characteristic parameters of arc were quantitatively changed. The influence of the tungsten electrode spacing, arc length, and deposition current on the coupling process and stability of the four TIG electric arc were analyzed and compared, thus obtaining the stable combustion mechanism of the four TIG electric arc and the key factors affecting the multi-arc thermal effect. The results show that for a certain range, the stability of the single tungsten electrode electric arc is better when the deposition current is less than or equal to 160 A, the arc length is less than or equal to 5 mm, and the tungsten electrode spacing is less than or equal to 6mm. Compared with the effect of tungsten electrode spacing, the influence of arc length and deposition current on the shape of the electric arc is relatively small. When the distance between tungsten electrodes was 2 mm, the tetra-tungsten arc attracted each other under the action of self-magnetic contraction and Lorentz force, the tetra-tungsten arc formed a common conductive channel, in this case, the stability of tetra-tungsten arc is the best, and the effective utilization rate of the heat source is the highest, which is nearly 9.2 times higher than that of the distance between tungsten electrodes is 10 mm, When the distance between tungsten electrodes was 8mm and 10mm, both the arc stability and the effective utilization of the heat source are significantly reduced. When the tungsten electrode spacing is 2mm, the arc energy utilization rate is nearly 9.2 times that of the tungsten electrode spacing of 10 mm.