CaO-Al2O3-MgO-SiO2 (CAMS)-based glass-ceramics were prepared using body crystallization method. Adding Cr2O3 into the ceramics not only effectively lowered the crystallization temperature, but also led to significant grain refinement of diopside that crystallized in the CAMS glass-ceramic after crystallization treatment at 900 degrees C for 2hours. Experimental work verified that the epitaxial growth of the diopside on the spinel particles, which formed during nucleation treatment when fabricating the glass-ceramics, facilitated the heterogeneous nucleation of diopside on the spinel and refined the diopside. In addition, two energetically favored crystallographic orientation relationships between the epitaxial growthdiopside and spinel were experimentally observed. They are [1)diopside. These two novel results can be potentially used to develop new glass-ceramic materials with improved performance.