The invention discloses an iron and slag separation and cooling device for on-line processing on molten iron desulphurization slag. The iron and slag separation and cooling device for on-line processing on molten iron desulphurization slag is configured according two modes including the off-line mode and the on-line mode. When configuration is carried out in the off-line processing mode, a lifting tipping device and a slag pot are arranged; and when configuration is carried out in the on-line processing mode, an on-line movement device is arranged. By adopting the iron and slag separation and cooling device for on-line processing on molten iron desulphurization slag, iron and slag can be quickly cooled while being completely separated, and quick and continuous industrial production is realized; two usage or configuration modes are set for one set of process, the core technology and equipment in the processing technology are kept the same whether in the on-line mode or the off-line mode; switch between the two working modes can be quickly realized so that the operating requirements in different occasions can be met, the purposes of being wide in application range, flexible in equipment configuration and easy to maintain are achieved, the processing efficiency is improved, and the investment cost is reduced.