Abstract: The energy consumption of the ventilation and air conditioning system in subway stations accounts for approximately 40% to 45% of the total energy consumption of the station. Conventional systems are often designed based on the most unfavorable operating conditions, maintaining high energy consumption even during low-load periods, resulting in significant energy waste. To tap into the potential for system energy saving and enhance operational efficiency, this paper takes a subway station in South China as the research object, conducts a comprehensive investigation and analysis of the current operation status of its ventilation and air conditioning system, and proposes and implements a low-cost integrated energy-saving renovation plan. This plan involves retrofitting fans and water pumps with variable frequency technology and equipping them with an intelligent control system based on real-time load feedback, enabling adaptive linkage and optimized operation of the system under different operating conditions. After the renovation, the effectiveness of the renovation plan was verified by monitoring the energy consumption of the system under different operating modes and comparing the data. The results showed that the comprehensive energy saving rate of the renovated system reached 36.3%, reducing energy consumption by approximately 414100 kW·h per year, and the energy efficiency improvement rate of the refrigeration system reached 35.2%. This empirical study demonstrates that the plan can significantly reduce energy consumption and enhance refrigeration energy efficiency, and it has the advantages of good economic benefits, minimal equipment modifications, and strong scalability. It can provide a reproducible engineering empirical reference for energy-saving renovation of existing subway station ventilation and air conditioning systems.