To address the challenges of high energy consumption and low utilization rate in the current grinding process of granite-type uranium ore, an intermittent microwave pretreatment method was proposed. Using granite as the research subject, intermittent microwave pretreatment was used to explore the effects of intermittent microwave pulse width, single cycle time and total pretreatment time on the strength degradation and damage evolution of granite. The results demonstrated that microwave pretreatment effectively reduced rock strength while promoting internal pore development. The increased total pore volume significantly exacerbated rock damage. In the intermittent microwave pretreatment, reducing the microwave pulse width and prolonging the intermittent time are beneficial to increasing the damage and strength weakening of granite. Under the optimal process parameters of intermittent microwave pretreatment, the compressive strength of granite was 148.02 MPa, the longitudinal wave velocity was 28.5% lower than that before treatment, and the damage variable D was 48.86%. Compared with continuous microwave pretreatment, the strength degradation and damage effect of granite under this condition were slightly lower than those of continuous microwave pretreatment, but the microwave energy output time was reduced by 400 s, which saved more than half of the microwave energy consumption. It provides a more energy-saving and effective pretreatment method for the mining and utilization of uranium ore and plays a certain role in promoting the development of microwave-assisted grinding technology.