The laser methane telemetry instrument consists of a transmitting unit and a receiving unit, both of which are integrated into one probe. The probe sends a laser beam to a distant surface, and the laser path is directed above the possible leakage point. The receiver receives feedback signals for calculation and processing. The design of the telemetry instrument is based on the TDLAS principle, and the molecular structure of methane has absorption properties for specific wavelengths of light. If there is a methane gas mass on the optical path, the emitted laser is partially absorbed, and the receiver can detect a proportional reduction in the number of gas mass molecules on the optical path and the optical signal. The telemetry instrument can respond sensitively, quickly, and stably to the measured gas in hazardous gas environments. The advanced open system is easy to use, and the built-in narrowband filter can effectively prevent sunlight from interfering with the signal. The telemetry instrument comes with a gear shifting mechanism that can automatically adjust the gear according to the strength of the received light.