Integrity Operating Window (IOW) is an important part of asset integrity management in oil and gas fields and chemical and refining companies at the process operation level. With the development of Hazard and Operability (HAZOP) and Risk Based Inspection (RBI) technology, IOW can enhance the process safety management by building interaction with Distributed Control System (DCS) operation, establishing in-depth integration with RBI and providing risk assessment basis for HAZOP. Through an introduction to the IOW standard, this paper focuses on the significance of the method, process, results and practical application of the first implementation of IOW in a deep-water gas field in the South China Sea. The results show that IOW technology can not only effectively upgrade the asset integrity management level and process safety management, it can also make contribution to the development of digital and intelligent oil and gas field. Therefore, it is recommended to apply IOW technology widely in all offshore oil and gas fields.