Demolition agent can fracutre rock and concrete by static expansive pressure generated by the hydration of CaO. In this study, three series of model experiments were conducted on the bench cut with demolition agent. They are composed of the experiments on the clarification of crack propagation mechanism, on the determination of hole diameter to spacing ratio and on the improvement of toe breaking techniques. The experimental results were discussed from the point of practical use of demolition agent in open pit or underground stopes.