The invention relates to an oil bottom case oil discharge plug seat welding device, which consists of a speed regulation motor, a bracket, position limiting blocks, a rotating mold, a compression mandrel, a welding gun, an angle regulator, an ascending and descending regulator, a left and right regulator, a support frame, a protection plate, an electric control box, a welding machine and the like, wherein the speed regulating motor drives the bracket to do horizontal rotation, a plurality of position limiting blocks are arranged on the bracket, the rotating mold is arranged on the position limiting blocks, a workpiece is fixedly arranged on the rotating mold through the compression mandrel, in addition, a welding hole of the workpiece is concentric with the rotating mold, the upper end of the workpiece is provided with the welding gun, the welding gun is arranged on the angle regulator, the angle regulator, the ascending and descending regulator and the left and right regulator form a whole and are fixedly arranged on the support frame, one side of the protection plate is provided with the electric control box, and the welding machine is placed at one side of the electric control box. The oil bottom case oil discharge plug seat welding device has the advantages that the automatic welding is realized, the quality is reliable, the safety performance is good, the production efficiency is high, and the like.