The one-step crystallization of CMS glass-ceramics was achieved by building Ca2+ and Mg2+ fast diffusion layer between the diopside crystal and the residual glass, as evidenced by SEM-EDXS and HTXRD. The probable explanation for this phenomenon is proposed as follows. During the crystallization, diopside crystals phase out from the homogeneous parent glass, concomitantly forming a glass layer between diopside crystal and residual glass. As experimentally observed, Na+ ions are rich in this layer, which promotes the formation of Sisingle bondOsingle bondNa bond. The Sisingle bondOsingle bondNa bonds further promote Ca2+ and Mg2+ ions diffusion in the glass layer. This layer eventually promotes further growth or ripening of the diopside crystals, leading to the nucleation and crystal growth of the CMS glass proceed continuously at Tnc. Thus, one-step crystallization of the CMS glass-ceramics becomes possible and practical.