Intelligent manufacturing is the combination of manufacturing technology and information technology, and it is developing towards automation, integration, informatization and greenness. In intelligent manufacturing, the sensing, analysis and decision-making are inseparable from the condition monitoring technology. Intelligent manufacturing takes the global monitoring of information flow as the basic clue, and is reflected through the precise regulation of manufacturing and working processes. The status monitoring and sensing technology is an important part of it. The on-line monitoring technologies applied in the cutting-cool wear, health state of numerical control machine, geometrical parameters, intelligent transmission device and oil status monitoring were discussed separetely, their characteristics were introduced as well as the corresponding research hotspots at home and abroad. Finally, the development trend in the future was summarized and prospected.