Methane contributes about one quarter to global warming and can affect the concentration of ozone， water vapor， hydroxyl groups and other components in the atmosphere. The inversion of vertical methane concentration is of great significance， and the sensitivity analysis of remote sensing detection and the selection of inversion wavelength are the basis of methane inversion. In this paper， based on the characteristics of the infrared Hyperspectral Vertical Atmospheric Sounder （HIRAS） on the Fengyun-3E star， we carry out forward simulation of atmospheric methane detection on the basis of the infrared atmospheric radiative transfer mechanism， and conduct detection sensitivity analysis and inversion wavelength selection. Firstly， the main absorption window of CH₄ and the main interference components are analyzed based on the high-resolution transmittance spectral line library （HITRAN）， and then based on the atmospheric profile background library and the instrumental parameters of HIRAS， the 1 200~1 400 cm^-1 band CH₄ and its interference elements （atmospheric temperature， surface temperature， surface emissivity，H₂O，N₂O，CO₂， F14， HNO₃ and O₃） detection sensitivity. The results show that the atmospheric temperature， surface temperature， surface emissivity， H₂O， and N₂O have a strong interfering effect on the irradiance brightness as well as the brightness temperature in the 1 200~1 400 cm^-1 band range. Finally， the information entropy principle based on the Jacobian matrix is used for the initial selection of CH₄ detection wavelengths， and combined with the results of detection sensitivity analysis， the selection of CH₄ inversion wavelengths for HIRAS detection is completed.