Considering the characteristics of the spectral shape variance during the Brillouin scattering process in optical fiber and the requirement of feature extraction at high accur acy,the wavelength dependence of Brillouin frequency shift and the characteristics of heterodyne de tection Brillouin scattering spectra for multi-wavelength probe light sensing are analyzed theor etically,and a method to extract features of superposed Brillouin scattering spectra based on Pseudo-Vo igt basis function and Levenberg-Marquard optimized algorithm is presented.A model of actual Brilloui n spectra is constructed by Gaussian white noise in the theoretical spectra for single-wavelength and mu lti-wavelength probe lights sensing,and the center frequency shift is 11.122903GH z.Compared with the Lorentzian, Gaussian and fifth-order polynomial curve fitting methods,the measurement erro rs of Brillouin frequency shift with Pseudo-Voigt curve fitting are the smallest,and the corre sponding measurement errors of temperature are 0.047 ℃,0℃ and 0.112℃.The evaluation parameters ar e better than those of other three curve fitting methods in the same test system. The simulation and experiment results show that the Pseudo-Voigt curve fitting is suitable for the features extraction of superpose d Brillouin spectra for multi-wavelength probe light sensing,and the prediction accuracy is improved eff iciently.