The invention belongs to the technical field of tin plate processing, and particularly relates to a double-reduced tin plate. A hot-dip tinning machine used in a production process of the tin plate comprises a shell, a tinning box and a sealing baffle plate, a placement plate is arranged at the position, close to the left side face of the shell, inside the shell, a cut strip plate is stacked on the upper surface of the placement plate, the tinning box is fixedly connected to the position, on the right side of the placement plate, inside the shell, and the sealing baffle plate is connected to the interior of the tinning box in a left-right sliding mode. By means of the machine, automatic tinning on the cut strip plate is effectively achieved, meanwhile, through a sealing structure, the tinning box is always isolated from outside air in a one-way mode while it is guaranteed that the cut strip plate is normally guided into the tinning box, so that liquid tin inside the tinning box is guaranteed not to make direct contact with air, the condition that the liquid tin liquid level is oxidized, so that the quality of the cut strip plate is influences is avoided, meanwhile, the problem thata large amount of tin gas generated by tin liquid evaporation is exhausted and pollutes the atmosphere is solved, and the tin plating quality is improved.