Abstract: Taking three core specifications (1.5, 2.5 mm² and 4 mm²) of small-cross-section cross-linked polyethylene (XLPE) insulated low-voltage power cables as the research objects, this study systematically explores the key influencing factors of thermal shrinkage performance, addresses the industrial problems of excessive thermal shrinkage rate and low first-pass qualification rate of such cables in production, and proposes a targeted full-process process optimization scheme. Through the multi-specification collaborative analysis of seven core production links including raw material selection, conductor preheating and extrusion method, the study quantitatively regulates each process parameter, supplements the test data of multi-specification parallel grouped samples, and clarifies the measures for instrument accuracy and environmental error control by adopting methods such as comparative test, parameter optimization and effect verification. The results show that for the three specifications of 1.5 mm², 2.5 mm² and 4 mm², the unified adoption of two-step silane cross-linked insulation material, conductor preheating at 70℃~90℃, semi-tubular extrusion with a draw ratio of 4~6, extrusion temperature of 170~204 ℃, production speed of 120 ~140 m·min^–1, gradient cooling process and cross-linking heat preservation parameter of 85 ℃ for 200 min can stably reduce the thermal shrinkage rate of the three specifications of cables to below 3%, and the first-pass qualification rate is increased from the original 53.3%~80% to 100%. This scheme realizes the standardized adaptation of process parameters for the three core specifications, effectively improves the quality stability of small-cross-section XLPE insulated cables, provides directly applicable technical support for cable manufacturing enterprises, and is of great significance for promoting the standardized upgrading of the production process of small-cross-section cables in the industry.