Granitic pegmatite shares similar modal and chemical compositions with eutectic granite, and has a genetic links with the highly fractionated granite. The LCTfamily, NYFfamily, and mixed LCT+NYFfamily pegmatites were classified petrogenetically, in which LCT pegmatites are peraluminous, characterized by enrichment of rare and alkali elements (Li, Rb, Cs, Be, Sn) and fluxing components (H2O, F, P, B), and very low Nb/Ta ratios (<5). In general, LCT pegmatite shows internal textural zonation, including the border, wall, intermediate and core zones; in addition, some of pegmatites maybe develop replacement bodies, layered aplites and miarolitic cavities. Most of LCT pegmatites intruded into metasedimentary rocks, typically at lowpressure amphibolite to upper greenschist facies under tectonic setting of late syncollision to early postcollision with respect to enclosing rocks. Aplitic textures in the outer zone (including border, wall zones and aplite) of pegmatites and UST (unidirectional solidification texture) have resulted from the liquidus undercooling of viscous granitic liquids prior to the onset of crystallization, while increasing crystal size in the internal zones (including intermediate and core zones), mineral zonations and crystallization of rare metal minerals have originated from a fluxenriched (H2O, F, P, B) and pileup of rare metal (Li, Rb, Cs, Be, Nb, Ta) boundary layer of liquid developed adjacent to the crystallization front by constitutional zone refining CZR mechanism. The onset of crystallization is closely related to liquidus undercooling state, while nucleation delay, crystal growth rate and nucleation density are dependent on the degree of liquidus undercooling. Up to now, the four main metallogenic mechanism proposed for pegmatitetype rare metal deposits include fractional crystallization, magmatic immiscibility, supercritical fluids and constitutional zone refining (CZR). For unzoned Li pegmatitic deposit (or whole vein Limineralized pegmatite), ore genesis is unclear as it could have resulted either from the magmatic immiscibility or Li strongly partitioning into magmatic fluids.