Functional crystal materials used as the important conversion media of light, sound and electricity, have been widely applied to high-tech fields such as energy, information, aerospace and related hot topics at the forefront of materials science and engineering subject. Crystallization process is the core of the preparation of functional materials, crystal growth habit of materials directly affects the functional performances of optical, electrical, magnetic, and catalytic behaviors. During the crystallization process of inorganic materials, crystals are microscopically transformed from free-state ions into the crystalline solid-phase. We can use the ionic electronegativity and microscopic symmetry changes of constituent components, to study the crystallization process of aggregation formation and structure evolution. Using molecular vibration spectroscopy we can at the molecular scale, reveal the crystallization process of nonlinear optical crystal materials in aqueous solution crystallization process, to overcome the lack of traditional means of in situ observations determining those non-long-range order structures. Chemical bonding theory of single crystal growth can from both thermodynamic and kinetic aspects of the whole system, effectively guide the growth of large crystals, reasonably regulate the growth surface and interface thermodynamics and kinetics. The chemical bonding theory of single crystal growth is applied to the design and optimization of growth parameters of large-size crystal pulling growth system, we have built up a large-size crystal growth system, and successfully grown o 2 sapphire crystals, o 3 YAG crystals, and o 4 lithium niobate crystals.