This study systematically investigates the thermal shrinkage behavior of cross-linked polyethylene (XLPE) insulation materials and their relation with cross-linking degree. Three XLPE samples with DCP contents (1, 1.5 and 2 phr) were prepared to establish distinct cross-linking degrees. The thermal shrinkage characteristics, melting temperatures, and crystallinity were analyzed. Samples underwent stretching at 90 ℃ and 110 ℃ followed by thermal shrinkage testing at 120 ℃. Results indicate that both excessively high and low cross-linking degrees amplify the curvature of thermal shrinkage curves. Notably, increased cross-linking degree correlates with elevated thermal shrinkage rate and higher steady-state shrinkage value. Lower stretching temperatures (90 ℃) induced more pronounced crystal structure disruption compared to 110 ℃, paradoxically resulting in enhanced shrinkage rates and steady-state shrinkage values. Otherwise, the cross-linking degree has little effect on steady-state shrinkage value at high stretching temperature. These findings provide critical insights for optimizing thermal shrinkage performance in XLPE cable insulation systems, offering theoretical guidance for material formulation and processing parameter selection.