Abstract: This paper takes the world's first fully commercial 1.2-kilometer 35 kV high-temperature superconducting (HTS) cable demonstration project in Shanghai as the research object, systematically elaborating the operation and maintenance system and practical achievements of the superconducting cable system. A long-term maintenance strategy for superconducting cables has been established through: a multi-level intelligent monitoring platform constructed by the superconducting cable body, cryogenic refrigeration system, and intelligent monitoring terminals; a coordinated operation and maintenance mechanism integrating cable body, refrigeration chain, and tunnel environment; a comprehensive three-in-one protection system combining on-site unattended operation, remote monitoring, and regular inspections; and hierarchical early warning technology based on multi-parameter threshold linkage. Guided by this maintenance strategy, the Shanghai 1.2-kilometer 35 kV superconducting cable project has achieved several years of continuous safe operation in a complex urban underground pipeline network environment, creating a world record for the engineering operation of high-temperature superconducting power equipment. The established operation and maintenance standard system provides a key technical paradigm for the large-scale deployment of superconducting cables in mega-city power grid renovation, green data center power supply, and new energy systems, marking a milestone transition of superconducting power transmission and distribution technology from laboratory verification to city-level engineering application.