This paper discusses the regularity about anisotropy properties of the fresh phyllite rock strength. The study takes the phyllite at a hydropower station dam site on Jinsha River as the research object. In the dam area, the engineering properties are very different between sericite phyllite and siliceous phyllite. Anisotropic properties of the two kinds of rock mass are selectively analyzed through a series of physical and mechanical tests researches. The change law of the phyllite rock strength is concluded relative to the included angle between its weak structure plane and compressive principal stress. In addition, the paper evaluates quantitatively the anisotropy of the phyllite with anisotropic rate index. So the authors acquire the law of phyllite engineering properties in the hydropower station dam site, which provides the basis for the accurate analysis of rock slope stability and surrounding rock mass of underground cavern.