The utility model discloses an adjustable thin plate welding tool which comprises a workbench and a bottom plate, an angle adjusting mechanism is arranged on the workbench, a height adjusting mechanism is arranged between the workbench and the bottom plate in a supporting mode, and a plurality of levelness adjusting mechanisms are evenly arranged at the bottom of the bottom plate. The welding angle of the thin plate is controlled by controlling the position of the sliding block; the welding angle can be accurately controlled according to the pointer installed on the rotating column and the dial gauge on the fixing block, the relative positions of the two plates can be adjusted through the sliding ways on the workbench and the upper supporting plate and the lower supporting plate, the clamping device is arranged, and the situation that in the welding process, the relative positions of the two plates are changed, and consequently the weld joint quality becomes poor is prevented. The power device drives the moving nut to move up and down to control the lifting height of the workbench so as to adapt to different welding conditions, the levelness of the tool is adjusted by adjusting thescrew-in depth of the levelness adjusting nut, and therefore the tool adapts to different ground conditions, and the welding precision is improved.