The PLC control system supporting the heating device of the gas heat storage oxidation shaft can realize the centralized control and management of the field data and instrumentation equipment. However, when the system or the working condition fails, it is necessary to carry out on-site troubleshooting and positioning through the on-site operator to trigger the fault. If a major fault is encountered, it needs to be technically processed by professionals to solve the fault. Therefore, the whole production process will be stagnant for a long time, which will seriously affect the production safety and quality of the enterprise. In this paper, through the analysis of the heating process of gas thermal storage oxidation wellbore, the overall functional architecture, fault tree, decision-making scheme process, process flow fault diagnosis, control system platform fault diagnosis and other aspects of the fault diagnosis system are analyzed, and the function and application of the fault diagnosis system are studied. Through trend prediction, precise positioning, timely response and other methods, the fault processing time of the device is obviously shortened, the reliability and safety of the device operation are improved, and good application results are achieved through practice.