Abstract: The safety and control characteristics of reactor driven by accelerator are studied with calculation and simulation running. The results show that reactor driven by accelerator do not happen prompt critical easily, its safety characteristics are better than critical reactor's, the higer the subcritical degree is, the better the safety is. The control loop of reactor driven by accelerator has a little time constant, a little overshoot, and short regulating time, its control characteristics also are better than critical reactor's.