This paper researched the application of intelligent diagnostic systems in the predictive maintenance of gas pressure regulating installations, analyzed the limitations of traditional maintenance modes in terms of cost, efficiency, and safety, and explored the advantages of intelligent diagnostic technology for pressure regulating installations in fault diagnosis and condition assessment. Through an actual case in Jinshan District of Shanghai, this paper verified the effectiveness of this technology in non-dismantling inspection, high-precision pressure monitoring, and intelligent diagnosis, and achieved accurate assessment and fault prediction for key components such as pressure regulators, shut-off valves, and relief valves. Research indicates that this diagnostic system significantly reduces maintenance costs, improves gas supply safety and equipment reliability, and provides a feasible path for the transformation of gas pressure regulating installations from scheduled maintenance to predictive maintenance.