Abstract: The shielding of the reactor hall of China Institute of Atomic Energy (CIAE) was reconstructed on the basis of the existing critical experimental device at CIAE, for guaranteeing the smooth work of validation experiment research on the coupling features between spallation target of the accelerator-driven sub-critical system (ADS) and the reactor. A shielding device consisting of polyethylene, cadmium, lead, steel and concrete is constructed to prevent the radiation leakage from the critical device and to control radiation on workers at a reasonable low level. The optimum design of shielding structure is completed by MCNP simulation calculation. In addition, based on the composite shielding structure composed of channel steel support structure, lead shielding layer, cadmium shielding layer and polyethylene shielding layer, a simplified model is established. The ANSYS finite element analysis program is used to calculate and analyze the stress of each part, which is less than the allowable stress, and the stability meets the requirements. The verification of theoretical calculation is completed with an engineering practice,

Key words: neutron shielding, structures analysis, finite element analysis