The local fracture and instability of granite in deep caverns have obvious time-dependent behaviors. In the present study, a coupled mechanism of granite nonlinear creep damage and strain softening was proposed, based on deep mine roadway engineering as the research background. Laboratory experiments were used to investigate the strain-softening and creep damage characteristics of granite, and the model parameters were then obtained by nonlinear fitting. A nonlinear Burgers model and viscoplastic strain-softening model were connected in series to construct a coupled model of granite nonlinear creep damage and strain softening, and the numerical solution was then obtained using the FLAC3D software. The results show that the accelerated creep curve calculated by the creep damage model was in good agreement with the experimental results. The proposed unified variable for granite strength damage and attenuation can characterize the evolution law of rock creep damage and strength attenuation. The coupled model was used to analyze the local fracture characteristics of surrounding rock in a deep cavern, and the calculation results were similar to the findings of practical engineering. The proposed coupled model is suitable for analyzing the deformation and fracture instability of surrounding rock in deep hard rock cavern engineering. [ABSTRACT FROM AUTHOR]