Abstract: Non-crosslinked thermoplastic polyolefin materials are key to developing environmentally friendly cables. Non-crosslinked polyethylene insulation, with low energy consumption and recyclability, has become a research hotspot. However, studies on matching non-crosslinked semi-conductive shielding materials with insulation materials remain scarce. In this study, linear low-density polyethylene (LLDPE) was used as the matrix resin to prepare shielding materials with different carbon black (CB) types and contents via melt blending. The physicochemical, electrical, and mechanical properties before and after aging were systematically investigated. The results show that after aging, the volume resistivity decreases, tensile strength increases rapidly in the initial stage and then plateaus, while the elongation at break exhibits a three-stage evolution: rapid decline, plateau, and secondary rapid decline. Higher CB content leads to a greater reduction in elongation at break after aging. Smaller CB particle size and higher structure degree result in better retention of elongation at break, indicating superior anti-aging performance. Due to the absence of a three-dimensional network constraint, the non-crosslinked polyethylene-based shielding material achieves high electrical conductivity at lower CB concentrations and exhibits improved long-term thermo-oxidative aging resistance. This study provides data support and a theoretical basis for the formulation optimization and life assessment of environmentally friendly polyethylene-insulated high-voltage cable shielding materials.