Abstract: This paper introduces the research results of the critical technologies and devices for one-dimensional linear laser length measurement in the field of geometric measurement, covering the frontiers of metrological technical institutions at home and abroad in the field of one-dimensional lines, measurement capability and range, elemental composition and working principle of the device, as well as the laser interference method for length measurement and the photoelectric microscope method for auto-focusing to achieve fast targeting of line pattern inscriptions. The research status of the one-dimensional linear laser length measurement device in China is elaborated, focusing on the characteristics of the critical technologies applied in the device and the current measurement level and capability. According to the recent technical development of one-dimensional linear measurement in China, the application prospect of one-dimensional linear measurement devices is discussed from two perspectives of line measurement value traceability and equipment manufacturing industry development.