In order to solve the problem of absorption line type selection in hydrogen leakage spectrum signal analysis of hydrogen-related equipment，a simulation model of hydrogen laser absorption spectrum direct absorption concentration inversion process is established. This research combined the HITRAN database to investigate the reconstruction accuracy of three types of line shape functions. The absorption coefficients obtained from the simulation results with those from the HITRAN database under different conditions of line shape function reconstruction are compared and analyzed. The influence of temperature variations on the absorption coefficients of hydrogen absorption lines under the three linear functions is examined. The results show that among the three linear functions，the Guass linear function has the highest reconstruction accuracy of hydrogen absorption spectral lines，and its reconstruction error is ≤ 0.02%，and the maximum reconstruction error of the Voigt line type function and the Lorentz line type function is 0.37% and 2.63%，respectively，which verifies the accuracy and reliability of the simulation model. As the temperature increases，the absorption coefficients of the three line types exhibit a linear decrease. The peak absorption coefficients decrease by 8.2%，16.8%，and 13.5% respectively，while the changes in the half-width are 4.5%，6.2%，and 5.2% respectively. The Lorentz line type exhibits the lowest temperature sensitivity for both the peak absorption and FWHM in hydrogen gas laser absorption spectra. Under the same temperature conditions，the peak absorption coefficient of Lorentz linear type is 6.3 times and 7.1 times that of Guass and Voigt linear type，and the absorption effect is the best. This study provides a basis for subsequent in-depth research on the selection of linear type detection by hydrogen laser absorption spectroscopy. Additionally，it offers theoretical guidance for practical applications.