With the development of the deep rock engineering, rockbursts are becoming more and more frequent. Regarding to the numerical simulation of rockbursts, both continuouum and discontinuum methods have certain limitations; whereas the continuum-discontinuum methods that combine advantages of both are more favorable and developing rapidly. In this study, a self-developed three-dimensional continuum-discontinuum method combining the Lagrangian element method and the discrete element method was developed into the parallelized acceleration version by GPU based on CUDA. To investigate mechanisms and processes of rockbursts, evolution of V-shaped notches and the element ejection phenomenon of the circular cavern surrounding rock under different hydrostatic pressures, lateral pressure coefficients and numbers of elements (maximum 1.0×106 ) were studied, and the evolution of the number of crack segments in the cavern surrounding rock was investigated. Results show that the support design based on the Fenner formula is unsafe for high hydrostatic pressures. Due to the changes in the positions of the V-shaped notches, the average maximum depth of the V-shaped notches increases slowly and then rapidly with the increase of the hydrostatic pressure. The simulation results of V-shaped notches in the cavern surrounding rock are in a good agreement with relevant experimental results, numerical results and field observations. The present GPU-parallelized computing shows more advantages for modeling of rockbursts than serial computing and commercial software computing.