Abstract: To address the issue of thermal shrinkage instability of the cross-linked polyethylene (XLPE) insulation layer in small-specification fire-resistant cables with a cross-section of 6 mm² or below, experiments were designed based on the thermal shrinkage mechanism and factors affecting friction force. Effects of contact surface material and wrapping process on insulation thermal shrinkage were investigated. Results showed that with increasing surface roughness of mica tape, both the contact area between insulation layer and mica tape and the friction force increased. Wrapping the outer polyethylene terephthalate (PET) of mica tape with the film facing outward could significantly increase the friction force. Thermal shrinkage rate of XLPE insulation layer with even wrapping was markedly reduced. Research results could provide a theoretical basis and engineering reference for improving the thermal shrinkage stability of insulation in small fire-resistant cables.