Deformation mechanism of rocks, especially microstructure study based on mineral deformation, has long been the study subject of structural geology. From near surface to deep lower crust, the deformation mechanism of felsic rocks convert gradually from brittle fracturing to ductile creep, and the deformation process have been imprinted in rocks in the form of corresponding microstructures. Generally, the deformation mechanism of a kind of mineral, from low temperaturepressure to high temperaturepressure, undergoes continuous transition from microcracks to dissolutionprecipitation process, to dislocation creep, to dynamic recrystallization, to grain boundary sliding or diffusion creep; and the transition process normally influences or interacts wiht each other. Feldspars are the most abundant rockforming minerals in the crust and its deformation behaviors can directly influence crustal rheologies. Therefore, study of microdeformation mechanism of feldspar is crucial to understanding the properties of crustal rheologies. Feldspars are a unqiue mineral which consists of mainly two end members: plagioclases and alkali feldspar. The both belongs to different crystal graph system and thus show different deformation behaviors. However, the both can change to each other one under certain temperaturepressure conditions. Hence, the difference of different kind of feldspar in physical and chemical properties makes the feldspar complex in deformation behavior. Begining with microdeformation mechanism of the rocks, this study described microstructural properties of feldspars, analyzed the performance of feldspar’s microstructural deformation under the different temperature conditions, compared the distinction of plagioclases and alkali feldspar, and summarized the influence of different microstructural deformation mechanisam on felspar’s CPO. And the study ended with brief introduction to the latest advances of methology and technology used in microstructures.