A method of principal component interactive validation in multi-region is presented.Based on the characteristic peaks of target gas the full spectral region is divided into multiple characteristic regions.In succession the principal component analysis around the pure components spectral matrix in divided characteristic regions is applied.Thus the potential components included in target gas are identified according to the main components number according to 99% larger cumulated contribution and the descending sorting of maximum value of pure component spectrums.After that, the characteristic regions of potential components are compared with the ones of target gas one by one.In this way the real components of target gas are confirmed.Because the principal component analysis was applied in multiple characteristic regions, this method can avoid omitted identification.Owning to the matching validation between the characteristic absorption regions of target gas and the ones of pure component gas this method can avoid additional identification.The simulated and the measured spectra both validate the qualitative ability of this method.