Abstract: For the welding of the cylinder in the washing tank, the automatic equipment was designed. The equipment consisted of feeding mechanism, rolling mechanism, handling equipment, clamping fixture, welding mechanism and unloading equipment. The batch feeding of plate was used, then the single plate was fed by vacuum adsorption. Through rolling mechanism, the plate was rolled to a cylinder. The fixture was used to clamp the cylinder in the horizontal and vertical direction. The rolled cylinder was welded by the argon arc welding. The testing result showed that the welds were tightness.