The invention belongs to the field of metallurgical and inorganic non-metallic materials and provides a die casting process method and device for producing microcrystalline glass by using blast furnace slag. The process method comprises the following steps that: (1) blast furnace slag kept in a temperature interval when the blast furnace slag is at a blast-furnace tap hole is transferred to a composition quenching, tempering and stirring tank, a modifier, a coloring agent and a nucleating agent are added into the tank, the obtained mixture is uniformly stirred, and the slag is kept in a high-temperature interval; (2) the slag enters various dies through slag inlets and are rapidly cooled and vitrified; (3) after he slag is continuously cooled until the temperature is not less than 500 DEG C, the slag is demoulded and enters a nucleating area, then the temperature of the slag rises to 700-800 DEG C, and the slag is subjected to heat preservation; (4) the slag is continuously heated and then enters a crystallization area; (5) the slag enters a cooling area to be cooled, thus obtaining a formed product; and (6) the formed product is subjected to surface grinding and polishing, thus obtaining finished product microcrystalline glass. According to the invention, blast furnace slag and solid waste resources are fully used, and the finished product microcrystalline glass has the advantages of high strength, corrosion resistance, multiple colors and the like, and has remarkable economic benefits and environmental protection benefits.