Dabie Mountain is a collision orogen between the Yangtze block and the North China block，Taihu-Susong area is located in the eastern segment of Dabie Mountain，and it is mainly composed of the metamorphic basement suffered different-grade metamorphism and a few low-grade metamorphic cover of the north edge of the Yangtze block. In this study， we selected muscovite of Susong metamorphic complex to make EPMA and X-ray powder diffraction analysis. The results showed that the multi-type of muscovite in Susong complex is 2M1 and is phengite. Among them，the average of lattice parameters b0 of phengite is 9.039，showing the metamorphic pressure of Susong metamorphic complex is medium-voltage to high-voltage. According to the microscopic deformation features of muscovite in Susong complex，we can know there are at least two period deformations，one leading to the pressure shadow of garnet and the right-handed structure of muscovite，which should correspond to the geological event which the middle and lower crustal material of Dabie orogen belt flowing to east parallel to the orogen belt in the Yanshanian. The other one results in the formation of muscovite's eddies structures，which should correspond to the collision events of the Yangtze plate and North China plate. According to the Ti-in-muscovite thermometers and phengite manometers，we can know that the conditions of Susong metamorphic complex are T=480 ℃～579 ℃，P=0.7～1.2 GPa，belongs to the greenschist facies to amphibolite facies.