The invention relates to an auxiliary protection gas hood of an automatic TIC welder head, and belongs to the field of machining. The auxiliary protection gas hood aims to solve the problem that oxidation of metal welding occurs easily near a welding pool in the welding process due to a small protection range of a welding nozzle of a traditional welder. According to the auxiliary protection gas hood, argon enters the auxiliary protection gas hood through a gas-guide tube, the turbulence phenomenon of the argon is reduced through filtering of a first netted plate and a second netted plate, and the argon around a welding gun forms a stable auxiliary argon flow field, so that the area outside of the nozzle of the welding gun and inside of the auxiliary protection gas hood is in the effective protection range of the argon, a good protection effect is achieved at the two sides of the welding pool in the automatic welding process of the easily oxidized metal tungsten electrode argon arc, and oxidation of titanium alloy and other easily oxidized metal is avoided. In the welding process, the auxiliary protection gas hood of the automatic TIC welder head and the welding gun form a whole, and the auxiliary protection gas hood swings along with the welding gun. The auxiliary protection gas hood of the automatic TIC welder head is suitable for the welding of the titanium alloy and other easily oxidized metal.