Abstract: The main points in this paper are: 1. The influences of various ratios of pyrite, quartz, kaolin, and reagent treatments of NaBH₄, HF, HCl on the IR spectra of kerogen are studied. 2. The IR spectrum data of pyrolysis simulation of kerogen are studied. 3. A synthetical appraise of the changes of 1700cm^-1/1600cm^-1, and 2900cm^-1/2000cm^-1 in IR spectra together with their significance and applicable range are made. 4. A new Index——The shifting rule of bands of aromatic ring is proposed. Along with the increase of the evolution of kerogen, the bands of aromatic ring skeleton vibration of 1600cm^-1 shifts regularly toward low wavenumber.This Index is suitable for comparing highly mature kerogen. Therefore it has great significance in study of Paleozoic carbonate rocks which are widely spread in China. Meanwhile the method of wavenumber shift is meaningful in developing the application of infrared spectrophotometry in petroleum geochemistry.