Oil shales from eight deposits in the central economic region of Mongolia were characterized and their pyrolysis experiments and thermogravimetric study were carried out. The Khoot deposit oil shale was chosen as the best-quality one with maximum shale oil yield. The optimum conditions (heating temperature 550 degrees C, heating rate 92 degrees C/min) were determined. Shale oil fractions with different boiling temperature intervals and hard residue were obtained by using ordinary distillation. These products can be used as gasoline, diesel, oil materials and binding materials (bitumen-like hard residue) after isolation of organic bases, acids and phenolic compounds. The Khoot deposit oil shale was investigated by thermogravimetric analysis enabling to explain the mechanism of oil shale thermal destruction process in detail. Thermal decomposition had the characteristics of a first-order reaction with activation energy 22.98 kcal/mol (96.28 kJ/mol) calculated from the oil shale thermogram.