Abstract: In this paper, strength properties of anisotropic rock have been measured for an argillaceous siltstone from somewhere. Under the condition of a series of different angles between the actual stress and the stratification planes, uniaxial compression test, Brazilian tensile test and double shear test have been conducted, and the ultimate strength of different orientations relative to the stratification planes have been obtained. The experimental results show that weak plane of foliated rocks has a marked effect on rock ultimate strength. Accordingly, we think it necessary to consider anisotropic properties of foliated rocks as one of the important factors in each test of rock ultimate strength.