Based on the significant effects of heat treatment on crystallization behaviors of glass-ceramics, influences of nucleation temperature and crystallization temperature on crystallization behavior of CaO-MgO-SiO2 glass-ceramics were studied. The results indicate that the main crystalline akermanite of the glass-ceramics converted into melilitite and the crystallization ability was improved with increasing nucleation and crystallization temperature, meanwhile, the minor crystalline phase diopside and forsterite were disappeared gradually.