In order to study the physical and mechanical properties of Beishan granite, conventional triaxial, creep, and relaxation tests were conducted. The main research process and conclusions are as follows:(1) Conventional triaxial compression tests were conducted on Beishan granite under different confining pressure conditions and mechanical characteristics, such as the deformation and failure modes of the samples, were compared and analyzed. It was found that the irreversible deformation of Beishan granite rock during failure was relatively small and there is no brittle ductile transition phenomenon with the increase of confining pressure; (2) Single stage creep tests on Beishan granite and multi-level creep tests were conducted under different confining pressure conditions and the deformation of different deviatoric stress pairs and the creep rate of single stage creep were analyzed, which showed that the creep form of Beishan granite was unstable creep, and its strain curve showed typical third-order creep characteristics; and (3) Single stage stress relaxation and cyclic relaxation tests were conducted on Beishan granite and the variation law of deviatoric stress was analyzed, which found that the deviatoric stress of Beishan granite decreased rapidly during the initial relaxation stage of stress relaxation process and reached a stable state in a relatively short period of time.