The Egongyan Bridge in Chongqing is a large steel box girder suspension bridge. The researchers detailed the welding procedures for the bridge's main girder, which is made up of 106 deck units. Each unit is 10m long, 35.5m wide, 3m deep, and weighs 132t. The steel box girder is fully welded, and the paper discusses the welding equipment arrangement, parameters for welding individual units, unit assembly, and quality inspections.