The invention belongs to the field of metallurgical and inorganic non-metallic materials and provides a continuous casting calendering process method and device for producing cast stone by using blast furnace slag. The process method comprises the following steps that: (1) blast furnace slag is transferred to a composition quenching, tempering and stirring tank, a modifier and a coloring agent are added into the tank, and the obtained mixture is uniformly stirred; (2) the slag enters a primary cooling area through a slag inlet and is formed primarily so as to obtain a blank shell, and then the blank shell enters a roller bed of a secondary cooling area; (3) the secondary cooling area ensures that the blank shell which is primarily formed successfully enters the roller bed of a heat insulated box to be cooled and finally formed; (4) the formed blank shell is cooled in the heat insulated box, an enamel material is sprayed on the formed blank shell to carry out surface coloring treatment, and then the obtained product is cooled so as to obtain a formed product; and (5) the formed product is cut into a set size and then is subjected to surface grinding and polishing, thus obtaining a finished cast stone product. According to the invention, blast furnace slag and waste resources are fully used, and produced cast stones are widely used, and have the characteristics of stable chromaticness, wear resistance, pressure withstanding, acid and alkali resistance, small expansion and shrinkage coefficients, and the like.