According to that the spectral line broadening of laser induced breakdown spectroscopy (LIBS) was lorentz nonlinear function model, using Levenberg-Marquardt(L-M) agorithm to optimally estimate the undetermined parameter in the function, the continuum background radiation and peak position and peak intensity were corrected, and the method of data points automatic extraction for fitting was analysed. Automatic fitting and feature parameter extraction for spectral data of LIBS based on L-M algorithm that was hybrid programming with matrixVB and VB were accomplished,and the result was compared with the origin7.5 data analysis software which was manual and commonly used and verified its stability and reliability.