Abstract: In order to solve the manufacturing problems of high arc pressure at high current and low manufacturing efficiency at low current with a single tungsten electrode, a four-tungsten-electrode arc heat source manufacturing method was proposed, and the arc physical characteristics were studied in detail. The physical characteristics of arc are the key factors for the stability of arc additive process. 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 160A, the arc length is less than or equal to 5mm, 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 2mm, 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 10mm, When the distance between tungsten electrodes was 8mm and 10mm, the tetra-tungsten arc couldn’t form a common conductive channel, Most of the electrons collide with each other under the action of the ampere force, eventually moving upwards towards the tungsten electrode, causing a decrease in the stability of the four-tungsten electrode arc and a decrease in the effective utilization of the heat source. When the tungsten electrode spacing is 2mm, the arc energy utilization rate is nearly 9.2 times that of the tungsten electrode spacing of 10mm.