Aiming at the problems of large measurement error, low accuracy,and poor anti-interference ability of non-cooperative target laser methane telemetry system,a set of methane integrated concentration telemetry simulation systems is established by using simulink software based on tunable diode laser absorption spectroscopy (TDLAS) and wavelength modulation spectroscopy (WMS) technology.The normalized second harmonic detection technology is used to remove environmental interference.The effects of sine wave frequency and modulation coefficient m on the normalized second harmonic signal are simulated and analyzed.The results show that m=2.2 is the best modulation coefficient,and the sine wave frequency has no effect on the normalized second harmonic signal.It is determined that the effective range of methane integral concentration detection is 0—2 000 ppm·m,within this range,the error of system simulation is -3.57%—4.06%.According to the simulation results,the relevant parameters of the telemeter are optimized and experimental research and analysis are carried out. The results show that the measurement error of the system is -4.68%—2.45%.The Allan variance analysis method is used to evaluate the stability and detection limit of the system.The lower detection limit of the system under the 5 s integration time is 37.85 ppm·m,the optimal integration time is 345 s,and the corresponding lower detection limit is 6.27 ppm·m.The research results are of great significance to the research and development of a high-precision laser methane telemetry system.