Method for accurately measuring gas density by spectrograph

The invention provides a method for accurately measuring gas density by a spectrograph, which belongs to the technical field of gas analysis, and comprises the following steps: after absorbing an optical signal reflected by a self-detection bin, the spectrograph processes the optical signal to obtain spectral information, and transmits the spectral information to an upper computer. Spectral data generated by various gases through a spectrograph under the conditions of different concentrations and different energy inputs are constructed, and the influence conditions of different gases on the spectrum under the conditions of different proportions after the different gases are combined are determined. The upper computer carries out retrieval in a sample library according to the received spectral information and determines a sample range, and component combination and concentration proportioning are carried out in the sample range, so that spectral data generated under the same condition are the same as the spect