Abstract: In order to further study mechanical protection performance of nylon sheathed power cables, based on the common types of cable sheath damage and the material characteristics of nylon sheath, advantages of nylon sheath in mechanical protection were discussed. Subsequently, combined with cable structure design, process realization of large outer diameter cables, and engineering verification analysis, important role of nylon sheathed power cables in improving mechanical properties, enhancing reliability and prolonging service life was expounded. Research results could provide technical support and theoretical basis for the further promotion and application of nylon sheathed power cables.