In order to know about the rheological properties of typical biotite granitic gneiss in Xiaowan Hydropower Project, triaxial rheological experiments with biotite granitic gneiss were carried out on the rock servo-controlling rheological testing machine. As a result the typical complete rheological curve of the biotite granitic gneiss indicates that when the stress level is low, the rheological deformation of rock specimen is not obvious; when in high stress conditions, the rock mass rheological properties are very significant with large rheological deformation, including three typical rheological phases. The rheological deformation decreases with the increase of the confining pressure, and at the same time the rheological rate of rock specimen changes with the change of stress level. In low stress state, the corresponding rheological rate of the rock specimen incarnated as the rheological rate attenuation stage and the rheological rate uniform stage, while once the stress level exceeds the long-term strength of rock specimen, the rheological rate would first decreases and then keep at a constant value, and finally it will trend to follow the non-linear acceleration law. The rupture form of the low-intensity biotite granitic gneiss specimen is the main crack surface which causes the damage of rock specimen, and finally generated by the expansion and transfixion of the crack in the initial cavern flaw. The rheological deformation and rupture form of rock specimen in different confining pressures are not exactly the same.