Methane is a gas whose content in the atmosphere is growing fast. With the development of human industrial emissions and animal husbandry, methane gas emissions are increasing, and the value of its impact on global warming is several times higher than that of carbon dioxide, so the accurate detection of methane is a focus and hotspot to cope with environmental problems. This study uses the SCIATRAN radiative transfer model to simulate the radiative transfer process of high-resolution spectroscopy. By controlling a single variable to change different observation geometries surface parameters and aerosol parameters, we simulate the changes of irradiance spectra of methane in the 1.6-band under different conditions of the near-surface detection environment and analyze the sensitivity parameters in the process of methane detection and study the sensitivity parameters for the process of detecting methane spectra. The sensitivity results are analyzed for high and low sensitivity parameters in detecting methane spectra. The results show that the solar zenith angle significantly affects the methane irradiance, and the influence of zenith angle change is as high as 83%. The variation of observation altitude near the ground has the least negligible effect on the methane irradiance spectra. The effect of aerosol type on the methane irradiance spectra is small, and the difference between the methane irradiance spectra under rural aerosol and no aerosol conditions is small; the effect of aerosol optical thickness on the methane irradiance spectra is regular, and the methane irradiance decreases when the value of optical thickness increases. Surface parameters had the greatest influence on the methane irradiance spectra, with a 66% difference in methane irradiance between different surface vegetation cover types. The methane irradiance at different surface albedos also varied regularly, with higher values of surface albedo leading to larger values of methane irradiance spectra. The study also verified the feasibility and accuracy of the SCIATRAN model for simulating methane spectra by comparing the simulated data with the measured data and provided sensitive data analysis for the inversion of methane spectra.