Abstract: Aiming at the study on the influence of mineral matter on DTA ther-mogram of kerogen, experiments with various minerals were carried out. The experiments show that. 1. coal, kerogen, bitumen and petroleum all have their own diagnostic peaks on DTA thermograms which could serve as a simple and reliable way to study the maturity of organic matters; 2. mineral matter, especialy pyrite, exert significant influences on DTA thermogram, but if the content of pyrite is less than 2‰ after dilution (i.e.the pyrite content in kerogen is less than 20%), it could be accepted within the permitted range of the sensitivity of the instrument, and there is no influence on the result.