Abstract: X-rays, as an important tool for detecting atomic-scale material structures, have been widely used in cutting-edge scientific research, medical diagnosis, and industrial inspection. X-ray free electron laser (XFEL), as one of the most advanced light sources in the world currently, with its ultra-high peak brightness, femtosecond-level pulses and full coherence characteristics, has significantly promoted the development and application of X-ray technology. Many countries and research institutions worldwide are actively promoting the construction and technical progress of XFEL facilities. This paper discusses the basic principles of XFEL, international research progress and latest technical breakthroughs, as well as China's research progress in XFEL technology, and provides a prospect for China's future XFEL technology.