Abstract: The present application discloses a method and a system for measuring a concentration of a gas to be measured by identifying features of an unknown gas. According to the method, a function model is constructed according to features of a known gas and features of a gas mixture, the features of the unknown gas are finally acquired by learning parameters in a training function, and the features of the unknown gas are incorporated into a feature library of the known gas, to provide more accurate parameters for obtaining the concentration of each component in the gas mixture through inversion calculation. The system includes a light source, a measuring cell, a spectrometer, a storage module, a learning and training module, an initialization module, and an inversion module.