Abstract: The optimization design and application study on shielding putty were carried out according to the marine nuclear power plant radiation field’s characteristic, need of radiation protection and environmental conditions. The modified bisphenol-A epoxy resin and amine curing agent were chosen as base materials owning anti-corrosion and mildew, strong adhesion, less toxicity characteristics and so on. At the same time, efficient shielding additives such as lead, polyethylene and boron carbide powders with particle size of about 100 μm were used to improve the radiation protection performance of shielding putty. Furthermore, the shielding putty component was optimized based on Monte Carlo method, and an optimum radiation protection level was achieved. The results show that when the shielding putty contains 5%-15% boron carbide and 80% lead, the neutron moderation and absorption levels achieve balance, and γ-ray shielding capability increases significantly because of high lead mass content, which could make the shielding putty to be the best radiation protection level. Finally, kinds of processing agents, such as defoamers, dispersants, leveling agents, accelerators, take important place in the solidification process, bubble outlet, mixing uniformity, molding densifying and so on. However, testing results proves that optimized shielding putty with excellent shielding capability, better molding quality, high bonding strength, convenient application property, is suitable for the radiation protection in application of biological shielding crack injection and anomalous area filling in the area of nuclear power plant facilities.