Abstract: Influencing factors for thermal elongation properties and thermal shrinkage properties of ultraviolet irradiation cross-linked polyethylene insulation were studied, and corresponding process optimization measures were proposed. Difficulties in actual production were solved by adjusting mixing ratio of materials, increasing temperature of conductors, adjusting position of the core in irradiation box, cooling in sections and changing extrusion mold, to improve product properties of ultraviolet irradiation cross-linked cables. Results showed that amount of color masterbatch, production line speed, ambient temperature, core position, irradiation dose and crosslinking dose had significant effects on thermal elongation properties. Segmented cooling and adjustment of mold tensile ratio could effectively control thermal shrinkage properties. Results could provide theoretical support and practical guidance for application of ultraviolet irradiation cross-linking technology, and help to improve quality and production efficiency of cable products.