High basicity glass-ceramics were synthesized from mainly steel slag using single-stage sintering method. The proportion of steel slag used in glass batch was 85 wt % of the total batch mixture. The preparation and crystallization behavior of steel slag-derived glass-ceramics were investigated using differential thermal analysis (DTA), physical and mechanical properties, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The crystallization of the glass is controlled by surface crystallization mechanism. The morphology of the crystals developed from ultrafine particles to lamellar and irregular granular crystals with the increasing of the heat treating temperature. Wallostonite (CaSiO₃) with the lamellar shape and diopsite (CaMgSi₂O₆) with irregular granular shape are the major phases in the glass-ceramics heat treated between 1000 to 1200°C, while akermanite (Ca₂MgSi₂O₇) phase disappeared. The optical properties of glass-ceramics were achieved while heat treated at 1150°C for 60 min: high linear shrinkage of 5.7% and high bending strength of 58.7 MPa.