The invention discloses a welding device suitable for batch machining of steel bar truss floor support plates. The welding device comprises a workbench, a welding mechanism, a storage table and a conveying mechanism, supporting legs are arranged on the left side and the right side of the bottom of the workbench, a support is installed at the upper end of the right side of the workbench, a lead screw structure is installed at the upper end in the support, a clamping base is installed at the bottom of an electric telescopic rod, a fixing rod is arranged on the inner wall of the rear side of the support, the welding mechanism is installed on the inner wall of the front side of the support, the storage table is arranged at the upper end of the right side of the workbench, and the conveying mechanism is installed on the left side of the workbench. According to the welding device suitable for batch machining of the steel bar truss floor support plates, the welding mechanism is arranged, through matched use of a fixing base, a first supporting arm, a second supporting arm, a welding gun and a welding head, in the welding process of a steel bar truss, the welding gun does not need to be manually held for operation, meanwhile, the production efficiency of the steel bar truss floor support plates is improved, and welding automation is achieved.