Abstract: As the cornerstone of modern manufacturing, the improvement of the intelligence level of CNC machine tools is directly related to production efficiency, product quality and the market competitiveness of enterprises. However, a series of challenges are still faced by the development and application of high-end CNC machine tools at present, which restricts their full efficiency in the intelligent manufacturing system. To accelerate the integration of information technology to deepen the intelligent transformation, the key technologies of CNC machine tools under the background of intelligent manufacturing are sorted out from four aspects: processing accuracy guarantee, comprehensive performance improvement, intelligent operation and maintenance, and intelligent integration. The thermal error modeling and active control technology based on deep learning, as well as the geometric error detection and compensation methods, are analyzed. The comprehensive performance evaluation methods of CNC machine tools, the reliability modeling methods and energy-saving control strategies under "poor information" conditions are also discussed. The CNC machine tool state monitoring system based on multi-source information fusion, the fault diagnosis technology based on machine learning, and the remaining life prediction methods of CNC machine tools are analyzed. The development status of the integrated application of technologies such as digital twins, the Internet of Things, and cloud manufacturing with CNC machine tools is sorted out, providing a reference for promoting the technological innovation and industrial upgrading of high-end CNC machine tools in China.