Danba muscovite pegmatite-type deposit in western Sichuan province is the second largest muscovite producing area. But the mineralizing mechanism is still stays in debate. Located at the the center part of the muscovite deposit in the northern Danba area, Buyigou gradually transfers from west to east migmatized metamorphic zone, partially-migmatized metamorphic zone to sillimazitized zone, along which Jiangjia, Xiajiangjia, Shuida and Erdaoqiao pegmatite mineralized veins are distributed. The peaking values of homogeneous temperature of fluid inclusions from these pegmatite veins along the WE-trending belt decrease; CO2-H2O inclusions decrease, but their salinity increases gradually. C, O and H isotopic analyses suggest that metallogenic fluid mainly consists of magmatic hydrothemal fluid with deep-sourced carbon, formation water, and CO2 from decarburization. The ratios of CO2/CH4 and CO2/N2 from the above-mentioned veins from inward to outward are also decreasing. All these features indicate an evolution process of metallogenic fluid: magmatic hydrothermal fluid carrying carbon from deep mantle immigrated outward from the deep Chunmiuchang dome, mixed with CO2 from decarburization at the partially-migmatized metamorphic zone, further was diluted by formation water at the sillimazitized zone: Therefore, the Danba muscovite deposit belongs to mixed genesis of magma and metamorphism.