In the manufacturing process of TIG welding augmented material,the reciprocating heating of arc not only changes the forming quality,microstructure and properties of augmented material components,but also has a great influence on the radiation intensity and temperature of arc plasma. In this paper,316 L stainless steel welding wire with a diameter of 1.0 mm was deposited in a single channel and multi-layer to study the arc physical characteristics of augmented 316 L stainless steel TIG welding. According to the characteristics of arc augmentation forming system,an optical acquisition test system for TIG welding augmentation arc was established to obtain the spectral information and arc image of augmentation arc. The arc temperatures of different layers were calculated by relative strength method. The unstable phenomena of the first four layers were analyzed. The influence of the number of additional layers on arc shape and arc temperature was obtained. It is helpful to understand the mechanism of TIG welding arc influence on augmentation forming and lay a foundation for the realization of automatic quality control in arc augmentation manufacturing process.