In order to reduce the impact of the chronic spectral deformation on TDLAS gas analyzer accuracy, a transfer and restoration method was proposed. By comparing the real time spectra with the calibration spectra for validation gas, the deformation coefficient is obtained. The process gas spectra share the same deformation mechanism with the validation gas. So the process spectra can be restored to the calibration state due to deformation transitivity. Consequently analyzer maintains the original fidelity. It solves the tough issue of spectra restoration for dynamic process gas. It requires no adjustment of hardware parameters of optical or electronics system. The spectra are restored through signal filtering, feature extraction and deformation coefficients calculation. In the simulation, the similarity measure maintained 99.999% between calibration spectra and restorated real time spectra. For the experimentally acquired CO2 gas spectra with different levels of deformation, the similarity measure maintained 99.9% between target spectra and real time spectra with Lagrangian interpolation restoration.