Weld joint repairing device for underground hydraulic support

The invention provides a weld joint repairing device for an underground hydraulic support. The weld joint repairing device comprises an isolation hood, a support, a welding system and a gas supply system. The isolation hood can be connected with the equipment to be treated, and the isolation hood and the equipment to be treated define a sealed space, so that gas in the sealed space is not exchanged with gas outside the isolation hood. The support is connected with equipment to be treated and located in the sealed space. At least one part of the welding system is located in the sealed space, the welding system is connected with the support, and the support can play a role in fixing the welding system. The gas supply system is communicated with the isolation hood and can convey protective gas into the sealed space, and the protective gas is conveyed into the isolation hood through the gas supply system, so that the effect of isolating underground gas is achieved, and the to-be-treated equipment is repaired unde