Abstract: With the wide application of low-smoke halogen-free polyolefin outer sheath cables, the repair of damaged outer sheath has become a critical link in ensuring performance and service life of cables. Focusing on cold shrinkage low-smoke halogen-free polyolefin outer sheath, material characteristics and structural design principles were analyzed, and a cold shrinkage repair scheme was designed. Varieties of test methods, including compatibility test, waterproof test, long-term aging test, resistance to external impact test, shrinkage test at incision after high and low temperature switch, ultraviolet (UV) test, water immersion test after aging, vibration test, bending test were used to verify the continuous operation reliability of repaired cable under 9 kinds of external environmental conditions, such as oil, immersion, thermal aging, ultraviolet light exposure, external force, hot and cold alternating incision displacement, immersion after aging, external vibration, bending subjected. Based on various test data, cold shrinkage low-smoke halogen-free polyolefin outer sheath repair scheme has high reliability, and has significant application value in improving stability of cable system, which could provide a reference for optimization and development of repair technology.