Three kinds of unique high-heat-resistant neutron shielding resins have been developed. One is an excellent resin in terms of light weight. Another is a high-neutron-shielding-performance resin with a heat-proof temperature of 200°C. The third is a resin improved up to a heat-proof temperature of 300°C. The neutron shielding performance of the resins was carried out using a 252Cf neutron source. The results show that the shielding performance of the resin with a heat-proof temperature of 200°C is better than the neutron shielding resins with heat-proof temperatures up to 200°C. And, the performance of the resin with a heat-proof temperature up to 300°C is almost the same as that of polyethylene. It can be concluded that high-heat-resistant resin is attractive as the neutron shielding material in a high-temperature environment.