In order to compare the accuracy of two spectrum fitting algorithms based on the Lorentzian model and the pseudo-Voigt model, a distributed optical fiber sensing principle based on Brillouin scattering is used. Firstly, the calculation results of the measured Brillouin spectra using the Lorentzian model and the pseudo-Voigt model are compared. Then, The Brillouin spectrum with different shapes and signal-to-noise ratios is generated numerically through the pseudo-Voigt model, and the Brillouin frequency shift is calculated using spectral fitting methods based on the Lorentzian model and the pseudo-Voigt model, respectively. Finally, the accuracy of these two algorithms is compared. The simulation results show that underdifferent Brillouin spectrum shapes and signal-to-noise ratio conditions, the computational accuracy of the spectrum fitting algorithm based on the Lorentzian model and the pseudo-Voigt model is similar, but the former requires less computation than the latter.