Abstract: Considering the potential safety hazards in the current concept design of accelerator driven nuclear system,sub-critical verification facility with auxiliary shut-down system is designed in this paper by using MCNP code.The core parameters can be adjusted by changing thermal zone pitch;the thickness of thermal area and the inserting depth of control rod,and simulation calculation and comparative analysis of multiplication factor is carried out,and k_eff can be modulated under various parameters.Finally,the shut-down margin and control rode effectiveness for different thermal pitches and fuel numbers are calculated,and the calculation results show that auxiliary shut-down system improves the safety of the accelerator driven system.