Lithium is an important strategic critical metal of which the pegmatite type lithium deposit is one of the main sources. The origin of pegmatite, and how lithium and other critical metals were enriched and mineralized during the process of granitic magmatic and hydrothermal evolution are important scientific issues that required close investigation. It is difficult to obtain reliable U- Pb isotope dating from zircon in pegmatite as it has high U content and is prone to metamorphism or recrystallization. In situ U- Pb dating of other accessory minerals and ore minerals such as apatite, columbite- group minerals, and cassiterite has been widely used for dating pegmatite and related mineralization. The pegmatitic emplacement and mineralization for pegmatite type lithium deposits are generally simultaneous, and some of them may have multi- stage mineralization. The geochemical types of pegmatites are mainly LCT (Li- Cs- Ta) type and NYF (Nb- Y- F) type, and also their mixed types. The petrogenesis includes two major models of magmatic crystallization differentiation and crustal anatexis; a variety of mineralogical and geochemical methods can be used to distinguish the two types of genesis. The metallogenic mechanism of pegmatite type lithium deposits includes the initial enrichment of ore- forming elements in the magma source area, the enrichment and precipitation of ore- forming elements in the magmatic process, and the behavior and enrichment of ore- forming elements in the magmatic- hydrothermal process. In situ microanalysis of common silicate minerals and ore minerals in pegmatite is an important method to study the mineralization process of lithium and other critical metals.