Abstract: Offshore oil and gas development is far away from the land, and communication and network deployment face great challenges. Intelligent sensing technology is one of the difficult problems that must be solved in the development of offshore intelligent drilling. Offshore intelligent drilling and completion technology is the organic integration of Marine drilling and completion engineering and advanced technologies such as artificial intelligence, big data and cloud computing, which can realize fine characterization, decision optimization and closed-loop control of offshore oil and gas drilling and completion process, greatly improving drilling and completion efficiency and oil and gas recovery efficiency. To this end, the current technical difficulties of offshore intelligent drilling and completion in infrastructure construction, intelligent drilling and intelligent wellbore are analyzed. The key technologies in the field of intelligent sensing in offshore drilling and completion are studied from four aspects, such as formation, tools, fluids and equipment, and an intelligent monitoring system for offshore drilling and completion is constructed to realize a comprehensive perception of the whole life cycle of offshore drilling and completion. After the application of the offshore intelligent drilling monitoring system, the platform was used without any safety accidents. The key technology of intelligent perception in offshore drilling and completion, as the basis for the construction of offshore intelligent drilling and completion, provides technical support for promoting the digital transformation and intelligent development of offshore oil and gas fields.