Mont-Carlo simulation was performed for shielding CCD chip of an accelerator-based thermal neutron radiography instrument from the γ-rays and neutrons. The simulation results were comparable with experimental data. The current shielding system was evaluated with this method. The dose rate of γ-rays and neutrons in the CCD chip was calculated and the influence of different shielding materials and geometry on γ dose rate and fast neutron flux density in the CCD chip was investigated. The simulation indicates that the current shielding design can satisfy the operation demands of the thermal neutron radiography instrument with thick target 9Be (d

n) reaction.