A laser detection platform with an open single path and short optical distance is constructed, and a Levenberg-Marquardt (L-M) algorithm based on linetype is proposed. The method uses second order derivative of Gaussian linetype and Lorenz linetype as the fitting function of L-M algorithm. The samples with oxygen volume fraction of 0%-21% are corrected. The results show that the correlation coefficients of oxygen content and peak is the highest in L-M algorithm correction based on Lorentz linetype (0.9995). The sample with oxygen volume fraction of 1% is measured several times on the basis of Lorentz linetype. Compared with the measured results before and after the correction, the predicted maximum deviations of oxygen volume fraction are 0.38% and 0.22%, respectively, and the root mean square errors of prediction are 0.25% and 0.16%, respectively.