Much slag occupied the land resources and caused severe damage to the ecological environment. A lot of work has been done on the reclaimation and utilization of slag. The composition, type and characteristics of slag were similar in some way to glass ceramics, which are architectural decoration materials or wearable and corrosion-proof materials with high quality and low price. In this paper, glass ceramics was prepared using hematite slag, which has not been cooled down in order to save energy. The optimum processing condition determined by orthogenesis test to prepare glass ceramics was hematite78.16%, CaF23.91%, CaO7.77%, coke10.16%.The smelting temperature is 1550 for 60 min and the crystallization time is 90 min. Microstructure analysis was studied by SEM. The microcrystalline structure was many petals, which was diopside crystal proved by X-ray analysis.