We develop an ultra-thin, highly filled, neutron-shielding material. This material exhibits a desirable neutron-shielding performance, and also has certain advantageous mechanical properties and uses. We study the physical properties of shielding materials with different polyolefins as base materials, and investigate the neutron-shielding performance of boron-containing and lithium-containing shielding materials. We furthermore report on the effect of additive amounts of functional additives on shielding properties and physical-chemical properties. We additionally study the effect of radiation crosslinking technology on shielding material properties. We show that, using ethylene-octene copolymer (POE) modified low-density polyethylene (PE-LD), the additive amounts of boron carbide (B4C) and nano-montmorillonite (OMMT) are 60–70% and 4%, respectively. The optimal radiation dose is 160 kGy, and the shielding materials exhibit good neutron-shielding performance and mechanical strength.