With the development of semiconductor lasers, tunable diode laser absorption spectroscopy (TDLAS) technology has achieved great development and rapid expansion of application fields. There have been more than 1000 kinds of TDLAS instruments, which are applied to continuous emission monitoring and industrial process control fields. According to the statistics, 5%-10% of all infrared gas sensors based on TDLAS technology are sold in the world every year. Dozens of gases are measured on-line with high sensitivity and precision by the TDLAS technology, and gas parameters, including concentration, temperature, velocity and pressure, are also determined, which provide important technical support for the development of various fields. This article reviews the principle and recent research of TDLAS technology, with introduction from six application fields, such as atmospheric environmental monitoring, industrial process monitoring, deep sea dissolved gases detection, breath analysis, flow field diagnosis, and liquid water measurement.