Abstract: Application status of key technologies of gas telemetry based on tunable diode laser absorption spectroscopy were introduced including tunable diode laser technology, signal noise reduction technology and trace gas detection technology. Some problems of the key technologies of gas telemetry were pointed out, such as unstable performance of tunable diode laser, short distance of gas telemetry, poor signal noise reduction effect and big error of trace gas detection. Development directions of the key technologies of gas telemetry were proposed, which were developing tunable diode laser with high performance, studying nonlinear and unstable signal noise reduction algorithm, and designing digital lock-in amplifier for underground.