Abstract：The investigation on the brittle failure behavior of rock mass containing flaws is one of the important research fields of solid mechanics，especially in rock mechanics. It is also significant for engineering and academic studies. An experimental method for investigating three-dimensional failure process of rock containing three- dimension pre-existing flaws is proposed. By employing this method，the three-dimensional failure behaviors of basalt specimen containing single pre-existing flaw with different angles are investigated. The following experimental results have been drawn. (1) Failure surface and peak strength of rock mass containing 3D flaw are influenced directly by propagation direction and volume of flaw. (2) For rock containing 3D flaw，the ratio of yield strength to peak strength equals 0.75–0.82，and average value is 0.78；the ratio of residual strength to peak strength equals 0.58–0.67，and average one is 0.63. For intact rock，the ratio of failure(residual) strength to peak strength has little changes.
